diff --git a/TTXSamples/TTXCheckUpdate/ttxcheckupdate.c b/TTXSamples/TTXCheckUpdate/ttxcheckupdate.c
index 880370ff7..62aed9311 100644
--- a/TTXSamples/TTXCheckUpdate/ttxcheckupdate.c
+++ b/TTXSamples/TTXCheckUpdate/ttxcheckupdate.c
@@ -35,6 +35,7 @@
 #include "teraterm.h"
 #include "tttypes.h"
 #include "ttplugin.h"
+#include "ttlib.h"
 
 #include "codeconv.h"
 #include "dlglib.h"
@@ -55,6 +56,7 @@ typedef struct {
 	PComVar cv;
 	version_one_t *versions;
 	size_t versions_count;
+	PReadIniFile ReadIniFile;
 } TInstVar;
 
 static TInstVar InstVar;
@@ -239,6 +241,18 @@ static void WINAPI TTXInit(PTTSet ts, PComVar cv)
 	pvar->cv = cv;
 }
 
+static void PASCAL TTXReadINIFile(const wchar_t *fileName, PTTSet ts)
+{
+	(pvar->ReadIniFile) (fileName, ts);
+	MessageBoxPosParentRelative = ts->MessageBoxPosParentRelative;
+}
+
+static void PASCAL TTXGetSetupHooks(TTXSetupHooks *hooks)
+{
+	pvar->ReadIniFile = *hooks->ReadIniFile;
+	*hooks->ReadIniFile = TTXReadINIFile;
+}
+
 static void WINAPI TTXModifyMenu(HMENU menu)
 {
 	static const DlgTextInfo MenuTextInfo[] = {
@@ -269,7 +283,7 @@ static TTXExports Exports = {
 
 	TTXInit,
 	NULL,
-	NULL,
+	TTXGetSetupHooks,
 	NULL,
 	NULL,
 	NULL,
diff --git a/doc/en/html/about/history.html b/doc/en/html/about/history.html
index e8740482a..7f963c8fe 100644
--- a/doc/en/html/about/history.html
+++ b/doc/en/html/about/history.html
@@ -67,12 +67,15 @@ <h3 id="teraterm_5.3">YYYY.MM.DD (Ver 5.3 not released yet)</h3>
       <li>Modified to <a href="../setup/teraterm-ssh.html#AuthBanner">display SSH authentication banner in VT window</a> regardless of receiving character code.
       <li>Keyboard setting dialog is moved to Keyboard tab of Additional setting dialog.</li>
       <li>MACRO: <a href="../macro/command/send.html">send</a> macro command check data and sends it as text or binary. added <a href="../macro/command/sendtext.html">sendtext</a> and <a href="../macro/command/sendbinary.html">sendbinary</a> macro command</li>
-      <li>Macro
+      <li>MACRO: password file using aes-256-ctr
         <ul>
           <li>added the <a href="../macro/command/setpassword2.html">setpassword2</a>, <a href="../macro/command/getpassword2.html">getpassword2</a>, <a href="../macro/command/ispassword2.html">ispassword2</a> and <a href="../macro/command/delpassword2.html">delpassword2</a> commands. The contents that is saved with setpassword2 command is protected by a password. This password file is not compatible with prior password file.</li>
         </ul>
+      <li>added the <a href="../macro/command/getttpos.html">getttpos</a> command to retrieve the display status, position, and size in the VT window of Tera Term.</li>
       </li>
       <li>Add ViewlogEditor argument on <a href="../menu/setup-additional-log.html#ViewlogEditorArg">Log Tab</a> in Additional settings.</li>
+      <li>Setup - Font was integrated into <a href="../menu/setup-additional-font.html">Font tab</a> of Additional settings.</li>
+      <li>Added the <a href="../setup/teraterm-misc.html#MessageBoxPosParentRelative">MessageBoxPosParentRelative</a> option to change the display position of the message box (excluding some) from the center of the screen to the center of the parent window.</li>
       <li>Setup - Font was integrated into <a href="../menu/setup-additional-font.html">Font tab</a> of Additional settings.
       <li>Add <a href="../menu/setup-additional-tcpip.html">TCP/IP tab</a> of Additional setting dialog.
         <ul>
diff --git a/doc/en/html/macro/command/getttpos.html b/doc/en/html/macro/command/getttpos.html
new file mode 100644
index 000000000..a068a902e
--- /dev/null
+++ b/doc/en/html/macro/command/getttpos.html
@@ -0,0 +1,108 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
+  "http://www.w3.org/TR/html4/strict.dtd">
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html; charset=Shift_JIS">
+  <title>getttpos</title>
+  <meta http-equiv="Content-Style-Type" content="text/css">
+  <link rel="stylesheet" href="../../style.css" type="text/css">
+</head>
+
+<body>
+
+
+<h1>getttpos</h1>
+
+<p>
+Retrieve the display status, position, and size of the VT window in Tera Term. <em>(version 5.3 or later)</em>
+</p>
+
+<h2>Format</h2>
+
+<pre class="macro-syntax">
+getttpos &lt;showflag&gt; &lt;window x&gt; &lt;window y&gt; &lt;window width&gt; &lt;window height&gt; &lt;client x&gt; &lt;client y&gt; &lt;client width&gt; &lt;client height&gt;
+</pre>
+
+<h2>Parameters</h2>
+
+<dl>
+	<dt class="macro">Integer variable &lt;showflag&gt;</dt>
+	<dd>The display status of the VT window is stored.<br>
+	    0 : Normal<br>
+	    1 : Minimized (Iconified)<br>
+	    2 : Maximized<br>
+	    3 : Hidden</dd>
+
+	<dt class="macro">Integer variable &lt;window x&gt;</dt>
+	<dd>The X coordinate of the top-left corner of the window area is stored. </dd>
+
+	<dt class="macro">Integer variable &lt;window y&gt;</dt>
+	<dd>The Y coordinate of the top-left corner of the window area is stored.</dd>
+
+	<dt class="macro">Integer variable &lt;window width&gt;</dt>
+	<dd>The width of the window area is stored.</dd>
+
+	<dt class="macro">Integer variable &lt;window height&gt;</dt>
+	<dd>The height of the window area is stored.</dd>
+
+	<dt class="macro">Integer variable &lt;client x&gt;</dt>
+	<dd>The X coordinate of the top-left corner of the client area is stored. </dd>
+
+	<dt class="macro">Integer variable &lt;client y&gt;</dt>
+	<dd>The Y coordinate of the top-left corner of the client area is stored.</dd>
+
+	<dt class="macro">Integer variable &lt;client width&gt;</dt>
+	<dd>The width of the client area is stored.</dd>
+
+	<dt class="macro">Integer variable &lt;client height&gt;</dt>
+	<dd>The height of the client area is stored.</dd>
+	</dd>
+
+</dl>
+
+<h2>Return Value</h2>
+
+<dl>
+	<dt class="macro">System variable &lt;result&gt;</dt>
+	<dd>If the information retrieval is successful, the value 0 is stored. <br>
+	    If it fails, the value -1 is stored.</dd>
+</dl>
+
+<h2>Remarks</h2>
+
+<p>
+The units for coordinates, width, and height are pixels.<br>
+The origin (0,0) refers to the top-left corner of the main display (primary display).<br>
+The window area refers to the entire application window, while the client area refers to the text display area excluding the title bar, menu bar, frame etc from the window area.<br>
+If the VT window is in a minimized or hidden state, the stored values for coordinates, width, and height are incorrect.<br>
+If the MACRO is not linked to Tera Term, it will result in a macro error and the execution of the macro will be temporarily paused.
+</p>
+
+<h2>Example</h2>
+
+<pre class="macro-example">
+testlink
+if result > 1 then
+  :start
+  getttpos showflag w_x w_y w_width w_height c_x c_y c_width c_height
+  if showflag != 3 then
+    if showflag = 1 then
+      showtt 1
+      goto start
+    endif
+    setdlgpos c_x c_y
+    sprintf2 str 'x=%d, y=%d, width=%d, height=%d' c_x c_y c_width c_height
+    messagebox str 'Client Area'
+  endif
+endif
+</pre>
+
+<h2>See also</h2>
+<ul>
+  <li><a href="testlink.html">testlink</a></li>
+  <li><a href="showtt.html">showtt</a></li>
+  <li><a href="setdlgpos.html">setdlgpos</a></li>
+</ul>
+
+</body>
+</html>
diff --git a/doc/en/html/macro/command/index.html b/doc/en/html/macro/command/index.html
index bd28c6db9..19b10905d 100644
--- a/doc/en/html/macro/command/index.html
+++ b/doc/en/html/macro/command/index.html
@@ -34,6 +34,7 @@ <h2>Communication commands</h2>
  <li><a href="gethostname.html">gethostname</a> (version 4.61 or later)
  <li><a href="getmodemstatus.html">getmodemstatus</a> (version 4.86 or later)
  <li><a href="gettitle.html">gettitle</a>
+ <li><a href="getttpos.html">getttpos</a> (version 5.3 or later)
  <li><a href="kmtfinish.html">kmtfinish</a>
  <li><a href="kmtget.html">kmtget</a>
  <li><a href="kmtrecv.html">kmtrecv</a>
diff --git a/doc/en/html/reference/build_with_cmake.md b/doc/en/html/reference/build_with_cmake.md
index 6837ed1b4..8ad8bb1bb 100644
--- a/doc/en/html/reference/build_with_cmake.md
+++ b/doc/en/html/reference/build_with_cmake.md
@@ -21,29 +21,27 @@
 
 Please execute below commands on the top of source tree.
 Use Visual Studio IDE
-```
-mkdir build_vs2022
-cd build_vs2022
-cmake .. -G "Visual Stuido 17 2022" -A Win32
-cmake --build . --config Release -j
-```
+
+    mkdir build_vs2022
+    cd build_vs2022
+    cmake .. -G "Visual Stuido 17 2022" -A Win32
+    cmake --build . --config Release -j
+
 To build installer
-```
-cmake --build . --config Release --target Install
-cmake --build . --config Release --target inno_setup
-cmake --build . --config Release --target zip
-```
+
+    cmake --build . --config Release --target Install
+    cmake --build . --config Release --target inno_setup
+    cmake --build . --config Release --target zip
 
 ### NMake (Visual Studio, very experimental)
 
 Execute vcvars32.bat,etc to prepare an environment where nmake, cl are avaiable,
 Run next commands.
-```
-mkdir build_nmake
-cd build_nmake
-cmake .. -G "NMake Makefiles" -DCMAKE_BUILD_TYPE=Release
-cmake --build . -j
-```
+
+    mkdir build_nmake
+    cd build_nmake
+    cmake .. -G "NMake Makefiles" -DCMAKE_BUILD_TYPE=Release
+    cmake --build . -j
 
 ### MinGW (very experimental)
 
@@ -51,17 +49,15 @@ cmake --build . -j
 - EXPERIMENTAL
 
 Please execute below commands on the top of source tree by using the cmake available on MinGW.
-```
-mkdir build_mingw
-cd build_mingw
-cmake .. -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release
-cmake --build . -j
-```
+
+    mkdir build_mingw
+    cd build_mingw
+    cmake .. -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release
+    cmake --build . -j
 
 When cygwin, linux
-```
-mkdir build_mingw_cygwin
-cd build_mingw_cygwin
-cmake .. -G "Unix Makefiles" -DCMAKE_TOOLCHAIN_FILE=../mingw.toolchain.cmake -DCMAKE_BUILD_TYPE=Release
-cmake --build . -j
-```
+
+    mkdir build_mingw_cygwin
+    cd build_mingw_cygwin
+    cmake .. -G "Unix Makefiles" -DCMAKE_TOOLCHAIN_FILE=../mingw.toolchain.cmake -DCMAKE_BUILD_TYPE=Release
+    cmake --build . -j
diff --git a/doc/en/html/reference/develop-memo.html b/doc/en/html/reference/develop-memo.html
index 17ca3ea7c..255edc2ff 100644
--- a/doc/en/html/reference/develop-memo.html
+++ b/doc/en/html/reference/develop-memo.html
@@ -28,7 +28,7 @@ <h2 id="ini-entry">Add entry to TERATERM.INI</h2>
 <h3>Entry name</h3>
 
 <p>
-Unfortunately, the confusing entries such as EnableFoo... and DisableBar... are included.<br />
+Unfortunately, the confusing entries such as EnableFoo... and DisableBar... are included.<br>
 It recommends that the new name like as Baz....
 </p>
 
@@ -37,23 +37,26 @@ <h3>Changes</h3>
 <ul>
   <li>source code
     <ul>
-      <li>read/write INI file<br />
+      <li>read/write INI file<br>
           teraterm\ttpset\ttset.c</li>
-      <li>struct tttset<br />
+      <li>struct tttset<br>
           teraterm\common\tttypes.h</li>
+          To make a plugin work in both Tera Term 4 (TT4) and Tera Term 5 (TT5), it is necessary to ensure compatibility with the structure of TT4.<br>
+          Therefore, new members should be added at the end.<br>
+          Similarly, any members that are no longer needed should not be deleted but renamed to reserve_XXX and kept.</li>
     </ul>
   </li>
   <li>Document
     <ul>
-      <li>All items of Tera Term setup file<br />
+      <li>All items of Tera Term setup file<br>
           setup/teraterm-ini.html</li>
-      <li>help for setup dialog (when UI for change is present in a dialog)<br />
+      <li>help for setup dialog (when UI for change is present in a dialog)<br>
           dialog page under menu</li>
-      <li>help for setup item (when UI for change is not present in a dialog)<br />
+      <li>help for setup item (when UI for change is not present in a dialog)<br>
           category page under setup</li>
     </ul>
   </li>
-  <li>Default INI file<br />
+  <li>Default INI file<br>
       installer\release\TERATERM.INI</li>
 </ul>
 
@@ -63,10 +66,10 @@ <h2 id="i18n">Support i18n message</h2>
 <h3>Add new i18n message</h3>
 
 <ul>
-  <li>Source code<br />
+  <li>Source code<br>
       Read langage file</li>
   <li>If a message is on dialog, put English message as default text</li>
-  <li>Modify language file<br />
+  <li>Modify language file<br>
       Modify files under installer/release/lang_utf8 folder.
     <ul>
       <li>English.lng (English)
@@ -113,28 +116,28 @@ <h2 id="add-macro-command">What to do when new macro command is added?</h2>
 <ul>
   <li>Coding
     <ul>
-      <li>get a new number of command internal ID.<br />
+      <li>get a new number of command internal ID.<br>
           ... teraterm/ttmacro/ttmparse.h</li>
-      <li>add a if statement to below function.<br />
+      <li>add a if statement to below function.<br>
           ... CheckReservedWord@teraterm/ttmacro/ttmparse.c</li>
-      <li>add a caller doing the macro command.<br />
+      <li>add a caller doing the macro command.<br>
           ... ExecCmnd@teraterm/ttmacro/ttl.c</li>
       <li>make a function code for the macro command.</li>
     </ul>
   </li>
   <li>Help topic
     <ul>
-      <li>make the command help file.<br />
+      <li>make the command help file.<br>
           ... doc/LANG/html/macro/command/hogefunc.html</li>
-      <li>add to command index page.<br />
+      <li>add to command index page.<br>
           ... doc/LANG/html/macro/command/index.html</li>
-      <li>add the file to help topic.<br />
+      <li>add the file to help topic.<br>
           ... doc/LANG/teraterm.hhc</li>
-      <li>get a new number of context ID in help page.<br />
-          The value is internal ID + 92000.<br />
+      <li>get a new number of context ID in help page.<br>
+          The value is internal ID + 92000.<br>
           ... teraterm/common/helpid.h</li>
-      <li>make the alias between context ID and calling file.<br />
-          Open the .hhp file by using Text Editor, added a html line in [ALIAS] tag.<br />
+      <li>make the alias between context ID and calling file.<br>
+          Open the .hhp file by using Text Editor, added a html line in [ALIAS] tag.<br>
           ... doc/LANG/teraterm.hhp</li>
     </ul>
   </li>
@@ -175,7 +178,7 @@ <h2 id="menu-id">Naming rule to add menu ID</h2>
 <h2 id="icon">Icon</h2>
 
 <p>
-Icon file includes 4bit 32px and 16px images, 32bit 256px, 48px, 32px and 16px images.<br />
+Icon file includes 4bit 32px and 16px images, 32bit 256px, 48px, 32px and 16px images.<br>
 Each icon files include following kind images.
 </p>
 
@@ -306,13 +309,13 @@ <h2 id="icon">Icon</h2>
 </table>
 
 <p>
-The store order of image files in icon file is "bit depth ASC", "pixel size DESC."<br />
+The store order of image files in icon file is "bit depth ASC", "pixel size DESC."<br>
 Otherwise, when a program load an icon image without specifying pixel size for get maximum size image, API returns first image.
 </p>
 
 <p>
-Icon file include 4-bit images.<br />
-Windows NT 4.0 supports only 4-bit icon. And notification area icon on Windows 2000 supports only 4-bit icon.<br />
+Icon file include 4-bit images.<br>
+Windows NT 4.0 supports only 4-bit icon. And notification area icon on Windows 2000 supports only 4-bit icon.<br>
 4-bit color palette is followings:
 </p>
 
@@ -550,7 +553,7 @@ <h3>Files</h3>
   </li>
   <li>Under add/manual folder of TeraTermProject/update_website repository
     <ul>
-      <li>License files for web site is managed in TeraTermProject/update_website repository.<br />
+      <li>License files for web site is managed in TeraTermProject/update_website repository.<br>
           Replace a license file when it is cahnged.</li>
     </ul>
   </li>
diff --git a/doc/en/html/setup/teraterm-ini.html b/doc/en/html/setup/teraterm-ini.html
index 4fadafab6..9904e1f2a 100644
--- a/doc/en/html/setup/teraterm-ini.html
+++ b/doc/en/html/setup/teraterm-ini.html
@@ -118,8 +118,8 @@ <h2>Tera Term</h2>
 	<tr>
 		<td id="AlphaBlendActive"><a href="../menu/setup-additional-visual.html#AlphaBlendActive">AlphaBlendActive</a></td>
 		<td style="width:250px;">255</td>
-		<td style="width:250px;">※</td>
-		<td>※<a href="#AlphaBlend">AlphaBlend</a>の設定値が使われる</td>
+		<td style="width:250px;">*</td>
+		<td>* the value of <a href="#AlphaBlend">AlphaBlend</a> setting is used.</td>
 	</tr>
 	<tr>
 		<td id="AlphaBlend"><a href="../menu/setup-additional-visual.html#AlphaBlend">AlphaBlend</a></td>
@@ -919,6 +919,12 @@ <h2>Tera Term</h2>
 		<td style="width:250px;">&lt;-</td>
 		<td></td>
 	</tr>
+	<tr>
+		<td id="MessageBoxPosParentRelative"><a href="teraterm-misc.html#MessageBoxPosParentRelative">MessageBoxPosParentRelative</a></td>
+		<td style="width:250px;">off</td>
+		<td style="width:250px;">&lt;-</td>
+		<td></td>
+	</tr>
 	<tr>
 		<td id="Meta8Bit"><a href="teraterm-term.html#Meta8Bit">Meta8Bit</a></td>
 		<td style="width:250px;">off</td>
diff --git a/doc/en/html/setup/teraterm-misc.html b/doc/en/html/setup/teraterm-misc.html
index fd180c55e..b443154c1 100644
--- a/doc/en/html/setup/teraterm-misc.html
+++ b/doc/en/html/setup/teraterm-misc.html
@@ -474,5 +474,22 @@ <h1 id="BracketedControlOnly">Limit bracketed pasting to cases containing contro
 BracketedControlOnly=off
 </pre>
 
+<h1 id="MessageBoxPosParentRelative">Display the message box in the center of the parent window</h1>
+
+<p>
+By default, the message box is displayed in the center of the display.<br>
+To display the message box in the center of the parent window, edit the MessageBoxPosParentRelative line in the [Tera Term] section as follows.<br>
+(Even if set MessageBoxPosParentRelative=on, some message boxes may still be displayed in the center of the display.)
+</p>
+
+<pre>
+MessageBoxPosParentRelative=on
+</pre>
+
+<pre>
+Default:
+MessageBoxPosParentRelative=off
+</pre>
+
 </BODY>
 </HTML>
diff --git a/doc/en/html/setup/teraterm.html b/doc/en/html/setup/teraterm.html
index b32e01841..b2bc78ec2 100644
--- a/doc/en/html/setup/teraterm.html
+++ b/doc/en/html/setup/teraterm.html
@@ -184,6 +184,7 @@ <h3>Miscellaneous</h3>
  <li><a href="teraterm-misc.html#IniAutoBackup">Auto backup of Tera Term setup file</a></li>
  <li><a href="teraterm-misc.html#BracketedSupport">Support bracketed paste</a></li>
  <li><a href="teraterm-misc.html#BracketedControlOnly">Limit bracketed pasting to cases containing control characters</a></li>
+ <li><a href="teraterm-misc.html#MessageBoxPosParentRelative">Display the message box in the center of the parent window</a></li>
 </ul>
 
 <h3>TTSSH</h3>
diff --git a/doc/en/teraterm.hhc b/doc/en/teraterm.hhc
index 93c9bcdb7..7c2fd9144 100644
--- a/doc/en/teraterm.hhc
+++ b/doc/en/teraterm.hhc
@@ -962,6 +962,11 @@
 					<param name="Local" value="html\macro\command\gettitle.html">
 					<param name="ImageNumber" value="11">
 					</OBJECT>
+				<LI> <OBJECT type="text/sitemap">
+					<param name="Name" value="getttpos">
+					<param name="Local" value="html\macro\command\getttpos.html">
+					<param name="ImageNumber" value="11">
+					</OBJECT>
 				<LI> <OBJECT type="text/sitemap">
 					<param name="Name" value="kmtfinish">
 					<param name="Local" value="html\macro\command\kmtfinish.html">
diff --git a/doc/en/teraterm.hhp b/doc/en/teraterm.hhp
index 1f29fef47..45017e414 100644
--- a/doc/en/teraterm.hhp
+++ b/doc/en/teraterm.hhp
@@ -282,6 +282,7 @@ HlpMacroCommandGetspecialfolder=html\macro\command\getspecialfolder.html
 HlpMacroCommandGettime=html\macro\command\gettime.html
 HlpMacroCommandGettitle=html\macro\command\gettitle.html
 HlpMacroCommandGetttdir=html\macro\command\getttdir.html
+HlpMacroCommandGetttpos=html\macro\command\getttpos.html
 HlpMacroCommandGetver=html\macro\command\getver.html
 HlpMacroCommandGoto=html\macro\command\goto.html
 HlpMacroCommandIfdefined=html\macro\command\ifdefined.html
@@ -325,6 +326,7 @@ HlpMacroCommandRotateright=html\macro\command\rotateright.html
 HlpMacroCommandScprecv=html\macro\command\scprecv.html
 HlpMacroCommandScpsend=html\macro\command\scpsend.html
 HlpMacroCommandSend=html\macro\command\send.html
+HlpMacroCommandSendbinary=html\macro\command\sendbinary.html
 HlpMacroCommandSendbreak=html\macro\command\sendbreak.html
 HlpMacroCommandSendbroadcast=html\macro\command\sendbroadcast.html
 HlpMacroCommandSendfile=html\macro\command\sendfile.html
@@ -333,6 +335,7 @@ HlpMacroCommandSendln=html\macro\command\sendln.html
 HlpMacroCommandSendlnbroadcast=html\macro\command\sendlnbroadcast.html
 HlpMacroCommandSendlnmulticast=html\macro\command\sendlnmulticast.html
 HlpMacroCommandSendmulticast=html\macro\command\sendmulticast.html
+HlpMacroCommandSendtext=html\macro\command\sendtext.html
 HlpMacroCommandSetdate=html\macro\command\setdate.html
 HlpMacroCommandSetdir=html\macro\command\setdir.html
 HlpMacroCommandSetdlgpos=html\macro\command\setdlgpos.html
diff --git a/doc/ja/html/about/history.html b/doc/ja/html/about/history.html
index 60f449a6a..71dbf986b 100644
--- a/doc/ja/html/about/history.html
+++ b/doc/ja/html/about/history.html
@@ -67,13 +67,15 @@ <h3 id="teraterm_5.3">YYYY.MM.DD (Ver 5.3 not released yet)</h3>
       <li><a href="../setup/teraterm-ssh.html#AuthBanner">SSH認証バナーをVT ウィンドウ内に表示する</a>時、受信文字コードによらず表示できるよう変更した。</li>
       <li>キーボード設定ダイアログを Additional settings の Keyboard タブへ移動した。</li>
       <li>MACRO: <a href="../macro/command/send.html">send</a> マクロコマンドは送信データを判定してテキスト又はバイナリとして送信する。<a href="../macro/command/sendtext.html">sendtext</a> と <a href="../macro/command/sendbinary.html">sendbinary</a> マクロコマンドを追加した。</li>
-      <li>マクロ
+      <li>MACRO: aes-256-ctrを使用したパスワードファイル
         <ul>
           <li><a href="../macro/command/setpassword2.html">setpassword2</a>, <a href="../macro/command/getpassword2.html">getpassword2</a>, <a href="../macro/command/ispassword2.html">ispassword2</a>, <a href="../macro/command/delpassword2.html">delpassword2</a> コマンドを追加した。setpassword2 コマンドで保存されたファイルの内容は、パスワードで保護される。このコマンドで扱われるパスワードファイルは、既存のパスワードファイルとは互換性がない。</li>
         </ul>
+      <li>MACRO: Tera Term の VT window の表示状態、位置、サイズを取得する <a href="../macro/command/getttpos.html">getttpos</a> コマンドを追加した。</li>
       </li>
       <li>Additional settings の <a href="../menu/setup-additional-log.html#ViewlogEditorArg">Log タブ</a>に ViewlogEditor の引き数を追加した。</li>
       <li>設定-フォント設定を Additional settings の <a href="../menu/setup-additional-font.html">フォントタブ</a>へ統合した。</li>
+      <li>メッセージボックス(一部を除く)の表示位置を画面中央から親ウィンドウ中央に変更する <a href="../setup/teraterm-misc.html#MessageBoxPosParentRelative">MessageBoxPosParentRelative</a> オプションを追加した。</li>
       <li>Additional settings に <a href="../menu/setup-additional-tcpip.html">TCP/IP タブ</a> を追加した。
         <ul>
           <li>TCP/IP setup ダイアログを TCP/IP タブへ移動した。</li>
diff --git a/doc/ja/html/macro/command/getttpos.html b/doc/ja/html/macro/command/getttpos.html
new file mode 100644
index 000000000..0cd63df35
--- /dev/null
+++ b/doc/ja/html/macro/command/getttpos.html
@@ -0,0 +1,106 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
+  "http://www.w3.org/TR/html4/strict.dtd">
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html; charset=Shift_JIS">
+  <title>getttpos</title>
+  <meta http-equiv="Content-Style-Type" content="text/css">
+  <link rel="stylesheet" href="../../style.css" type="text/css">
+</head>
+
+<body>
+
+
+<h1>getttpos</h1>
+
+<p>
+Tera Term の VT window の表示状態、位置、サイズを取得する。<em>(バージョン5.3以降)</em>
+</p>
+
+<h2>形式</h2>
+
+<pre class="macro-syntax">
+getttpos &lt;showflag&gt; &lt;window x&gt; &lt;window y&gt; &lt;window width&gt; &lt;window height&gt; &lt;client x&gt; &lt;client y&gt; &lt;client width&gt; &lt;client height&gt;
+</pre>
+
+<h2>パラメータ</h2>
+
+<dl>
+	<dt class="macro">整数型変数 &lt;showflag&gt;</dt>
+	<dd>VT windowの表示状態が格納される。<br>
+	    0 : 通常状態<br>
+	    1 : 最小化状態<br>
+	    2 : 最大化状態<br>
+	    3 : 非表示状態</dd>
+
+	<dt class="macro">整数型変数 &lt;window x&gt;</dt>
+	<dd>ウィンドウ領域左上隅の X 座標が格納される。</dd>
+
+	<dt class="macro">整数型変数 &lt;window y&gt;</dt>
+	<dd>ウィンドウ領域左上隅の Y 座標が格納される。</dd>
+
+	<dt class="macro">整数型変数 &lt;window width&gt;</dt>
+	<dd>ウィンドウ領域の幅が格納される。</dd>
+
+	<dt class="macro">整数型変数 &lt;window height&gt;</dt>
+	<dd>ウィンドウ領域の高さが格納される。</dd>
+
+	<dt class="macro">整数型変数 &lt;client x&gt;</dt>
+	<dd>クライアント領域左上隅の X 座標が格納される。</dd>
+
+	<dt class="macro">整数型変数 &lt;client y&gt;</dt>
+	<dd>クライアント領域左上隅の Y 座標が格納される。</dd>
+
+	<dt class="macro">整数型変数 &lt;client width&gt;</dt>
+	<dd>クライアント領域の幅が格納される。</dd>
+
+	<dt class="macro">整数型変数 &lt;client height&gt;</dt>
+	<dd>クライアント領域の高さが格納される。</dd>
+	</dd>
+</dl>
+
+<h2>返り値</h2>
+
+<dl>
+	<dt class="macro">システム変数 &lt;result&gt;</dt>
+	<dd>情報取得に成功した場合は 0 が、失敗した場合は -1 が格納される。</dd>
+</dl>
+
+<h2>解説</h2>
+
+<p>
+座標、幅、高さの単位はピクセル。<br>
+座標の原点 (0,0) はメインディスプレイ(プライマリディスプレイ)の左上隅の位置。<br>
+ウィンドウ領域はアプリケーションウィンドウ全体を、クライアント領域はウィンドウ領域からタイトルバー/メニューバー/フレーム等を除いたテキスト表示領域を指す。<br>
+VT windowが最小化状態または非表示状態の場合は、座標、幅、高さは誤った値が格納される。<br>
+MACRO が Tera Term とリンクされていない場合は、マクロエラーとなりマクロの実行が一時停止する。
+</p>
+
+<h2>例</h2>
+
+<pre class="macro-example">
+testlink
+if result > 1 then
+  :start
+  getttpos showflag w_x w_y w_width w_height c_x c_y c_width c_height
+  if showflag != 3 then
+    if showflag = 1 then
+      showtt 1
+      goto start
+    endif
+    setdlgpos c_x c_y
+    sprintf2 str 'x=%d, y=%d, width=%d, height=%d' c_x c_y c_width c_height
+    messagebox str 'Client Area'
+  endif
+endif
+</pre>
+
+<h2>参照</h2>
+<ul>
+  <li><a href="testlink.html">testlink</a></li>
+  <li><a href="showtt.html">showtt</a></li>
+  <li><a href="setdlgpos.html">setdlgpos</a></li>
+</ul>
+
+</body>
+</html>
diff --git a/doc/ja/html/macro/command/index.html b/doc/ja/html/macro/command/index.html
index 0ef8550c8..46f184592 100644
--- a/doc/ja/html/macro/command/index.html
+++ b/doc/ja/html/macro/command/index.html
@@ -34,6 +34,7 @@
  <li><a href="gethostname.html">gethostname</a> (バージョン 4.61以降)
  <li><a href="getmodemstatus.html">getmodemstatus</a> (バージョン 4.86以降)
  <li><a href="gettitle.html">gettitle</a>
+ <li><a href="getttpos.html">getttpos</a> (バージョン 5.3以降)
  <li><a href="kmtfinish.html">kmtfinish</a>
  <li><a href="kmtget.html">kmtget</a>
  <li><a href="kmtrecv.html">kmtrecv</a>
diff --git a/doc/ja/html/reference/build_with_cmake.md b/doc/ja/html/reference/build_with_cmake.md
index 40d8c9e61..95e05c733 100644
--- a/doc/ja/html/reference/build_with_cmake.md
+++ b/doc/ja/html/reference/build_with_cmake.md
@@ -22,29 +22,27 @@
 ### Visual Studio
 
 Visual Studio 縺ｮ IDE 繧剃ｽｿ逕ｨ縺吶ｋ蝣ｴ蜷医�萓�
-```
-mkdir build_vs2022
-cd build_vs2022
-cmake .. -G "Visual Stuido 17 2022" -A Win32
-cmake --build . --config Release -j
-```
+
+    mkdir build_vs2022`
+    cd build_vs2022
+    cmake .. -G "Visual Stuido 17 2022" -A Win32
+    cmake --build . --config Release -j
+
 繧､繝ｳ繧ｹ繝医�繝ｩ繧剃ｽ懈�縺吶ｋ
-```
-cmake --build . --config Release --target Install
-cmake --build . --config Release --target inno_setup
-cmake --build . --config Release --target zip
-```
+
+    cmake --build . --config Release --target Install
+    cmake --build . --config Release --target inno_setup
+    cmake --build . --config Release --target zip
 
 ### NMake (Visual Studio, very experimental)
 
 vcvars32.bat 繧貞ｮ溯｡後＠縺ｦ縺翫￥縺ｪ縺ｩ縺励※
 nmake縺悟茜逕ｨ縺ｧ縺阪ｋ迺ｰ蠅�°繧画ｬ｡縺ｮ繧医≧縺ｫ螳溯｡後＠縺ｾ縺吶�
-```
-mkdir build_nmake
-cd build_nmake
-cmake .. -G "NMake Makefiles" -DCMAKE_BUILD_TYPE=Release
-cmake --build . -j
-```
+
+    mkdir build_nmake
+    cd build_nmake
+    cmake .. -G "NMake Makefiles" -DCMAKE_BUILD_TYPE=Release
+    cmake --build . -j
 
 ### MinGW (very experimental)
 
@@ -52,17 +50,15 @@ cmake --build . -j
 - 螳滄ｨ鍋噪菴咲ｽｮ縺･縺代〒縺�
 
 msys2遲峨ｒ縺､縺九▲縺ｦMinGW縺御ｽｿ縺医ｋ迺ｰ蠅�°繧画ｬ｡縺ｮ繧医≧縺ｫ螳溯｡後＠縺ｾ縺吶�
-```
-mkdir build_mingw
-cd build_mingw
-cmake .. -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release
-cmake --build . -j
-```
+
+    mkdir build_mingw
+    cd build_mingw
+    cmake .. -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release
+    cmake --build . -j
 
 cygwin,linux遲峨〒縺ｯ谺｡縺ｮ繧医≧縺ｫ螳溯｡後＠縺ｾ縺吶�
-```
-mkdir build_mingw_cygwin
-cd build_mingw_cygwin
-cmake .. -G "Unix Makefiles" -DCMAKE_TOOLCHAIN_FILE=../mingw.toolchain.cmake -DCMAKE_BUILD_TYPE=Release
-cmake --build . -j
-```
+
+    mkdir build_mingw_cygwin
+    cd build_mingw_cygwin
+    cmake .. -G "Unix Makefiles" -DCMAKE_TOOLCHAIN_FILE=../mingw.toolchain.cmake -DCMAKE_BUILD_TYPE=Release
+    cmake --build . -j
diff --git a/doc/ja/html/reference/develop-memo.html b/doc/ja/html/reference/develop-memo.html
index 79750ffb7..aeeb38fdc 100644
--- a/doc/ja/html/reference/develop-memo.html
+++ b/doc/ja/html/reference/develop-memo.html
@@ -28,7 +28,7 @@
 <h3>項目名</h3>
 
 <p>
-すでに EnableFoo... や DisableBar... が混在してしまっているが、混乱しやすい。<br />
+すでに EnableFoo... や DisableBar... が混在してしまっているが、混乱しやすい。<br>
 今後は Baz... という形式にするのが望ましい。
 </p>
 
@@ -37,23 +37,26 @@
 <ul>
   <li>ソースコード
     <ul>
-      <li>INI ファイルの読み書き部分<br />
+      <li>INI ファイルの読み書き部分<br>
           teraterm\ttpset\ttset.c</li>
-      <li>tttset 構造体<br />
-          teraterm\common\tttypes.h</li>
+      <li>tttset 構造体<br>
+          teraterm\common\tttypes.h<br>
+          Tera Term 4(TT4) と Tera Term 5(TT5) の両方でプラグインを動作させるには TT4 の構造体と互換性を持たせる必要がある<br>
+          そのため、新しいメンバーは末尾に追加する<br>
+          同様に、使用しなくなったメンバーは削除せず reserve_XXX にリネームして残しておく</li>
     </ul>
   </li>
   <li>ドキュメント
     <ul>
-      <li>Tera Term 設定ファイルの全項目一覧<br />
+      <li>Tera Term 設定ファイルの全項目一覧<br>
           setup/teraterm-ini.html</li>
-      <li>設定ダイアログのヘルプ（ダイアログに変更 UI がある場合）<br />
+      <li>設定ダイアログのヘルプ（ダイアログに変更 UI がある場合）<br>
           menu 以下のダイアログのページ</li>
-      <li>設定項目のヘルプ（ダイアログに変更 UI がない場合）<br />
+      <li>設定項目のヘルプ（ダイアログに変更 UI がない場合）<br>
           setup 以下の該当する分類のページ</li>
     </ul>
   </li>
-  <li>デフォルトの INI ファイル<br />
+  <li>デフォルトの INI ファイル<br>
       installer\release\TERATERM.INI</li>
 </ul>
 
@@ -63,10 +66,10 @@
 <h3>新しく国際化メッセージに対応する</h3>
 
 <ul>
-  <li>ソースコード<br />
+  <li>ソースコード<br>
       言語ファイルを読み込む</li>
   <li>ダイアログのメッセージの場合には、リソースファイルに英語のメッセージをデフォルトのテキストとして記述する</li>
-  <li>言語ファイルを修正する<br />
+  <li>言語ファイルを修正する<br>
       修正するのは installer/release/lang_utf8 配下の言語ファイル
     <ul>
       <li>English.lng（英語）
@@ -117,28 +120,28 @@
 <ul>
   <li>ソースコードの修正
     <ul>
-      <li>コマンドの内部 ID を採番する。（「内部 ID」は"helpid.h"にも使用される）<br />
+      <li>コマンドの内部 ID を採番する。（「内部 ID」は"helpid.h"にも使用される）<br>
           ... teraterm/ttmacro/ttmparse.h</li>
-      <li>コマンド名を走査して内部 ID に変換する。<br />
+      <li>コマンド名を走査して内部 ID に変換する。<br>
           ... CheckReservedWord@teraterm/ttmacro/ttmparse.c</li>
-      <li>コマンドの内部 ID から実際に処理をする関数を呼ぶ。<br />
+      <li>コマンドの内部 ID から実際に処理をする関数を呼ぶ。<br>
           ... ExecCmnd@teraterm/ttmacro/ttl.c</li>
       <li>処理する関数を作る。</li>
     </ul>
   </li>
   <li>ヘルプ(言語ごと)
     <ul>
-      <li>コマンドのヘルプを作る。<br />
+      <li>コマンドのヘルプを作る。<br>
           ... doc/LANG/html/macro/command/hogefunc.html</li>
-      <li>コマンド一覧ページに追加する。<br />
+      <li>コマンド一覧ページに追加する。<br>
           ... doc/LANG/html/macro/command/index.html</li>
-      <li>ヘルプトピックに追加する。<br />
+      <li>ヘルプトピックに追加する。<br>
           ... doc/LANG/teraterm.hhc</li>
-      <li>ヘルプページのコンテキスト ID を採番する。<br />
-          値は コマンドの内部 ID + 92000。<br />
+      <li>ヘルプページのコンテキスト ID を採番する。<br>
+          値は コマンドの内部 ID + 92000。<br>
           ... teraterm/common/helpid.h</li>
-      <li>コンテキスト ID と呼び出すファイルのエイリアスを作成する。<br />
-          テキストエディタで直接開き、[ALIAS]にHTMLを追加する。<br />
+      <li>コンテキスト ID と呼び出すファイルのエイリアスを作成する。<br>
+          テキストエディタで直接開き、[ALIAS]にHTMLを追加する。<br>
           ... doc/LANG/teraterm.hhp</li>
     </ul>
   </li>
@@ -179,7 +182,7 @@
 <h2 id="icon">アイコン</h2>
 
 <p>
-アイコンファイルには、4bit の 32px, 16px 画像、32bit の 256px, 48px, 32px, 16px 画像を含めます。<br />
+アイコンファイルには、4bit の 32px, 16px 画像、32bit の 256px, 48px, 32px, 16px 画像を含めます。<br>
 各アイコンファイルには以下の種類の画像が含まれています。
 </p>
 
@@ -310,13 +313,13 @@
 </table>
 
 <p>
-アイコンファイルへの画像の格納順は「ビット数が小さい順、サイズが大きい順」とします。<br />
+アイコンファイルへの画像の格納順は「ビット数が小さい順、サイズが大きい順」とします。<br>
 そうでないと、プログラムがサイズを指定せずに「最大サイズの画像」を取得しようとしたときに「最初の画像」が取り出されるためです。
 </p>
 
 <p>
-アイコンファイルには 4bit 画像を含めます。<br />
-Windows NT 4.0 は 4bit アイコンのみサポートしているためです。また、Windows 2000 の通知領域も 4bit アイコンのみサポートしています。<br />
+アイコンファイルには 4bit 画像を含めます。<br>
+Windows NT 4.0 は 4bit アイコンのみサポートしているためです。また、Windows 2000 の通知領域も 4bit アイコンのみサポートしています。<br>
 4bit アイコンには以下の色が使用できます。
 </p>
 
@@ -554,7 +557,7 @@
   </li>
   <li>TeraTermProject/update_website リポジトリの add/manual フォルダ配下
     <ul>
-      <li>Web サイトで表示するライセンスファイルは TeraTermProject/update_website リポジトリで管理している。<br />
+      <li>Web サイトで表示するライセンスファイルは TeraTermProject/update_website リポジトリで管理している。<br>
           ライセンスファイルに変更があれば差し替える。</li>
     </ul>
   </li>
diff --git a/doc/ja/html/setup/teraterm-ini.html b/doc/ja/html/setup/teraterm-ini.html
index a48c75005..5ce745e82 100644
--- a/doc/ja/html/setup/teraterm-ini.html
+++ b/doc/ja/html/setup/teraterm-ini.html
@@ -919,6 +919,12 @@ <h2>Tera Term</h2>
 		<td style="width:250px;">&lt;-</td>
 		<td></td>
 	</tr>
+	<tr>
+		<td id="MessageBoxPosParentRelative"><a href="teraterm-misc.html#MessageBoxPosParentRelative">MessageBoxPosParentRelative</a></td>
+		<td style="width:250px;">off</td>
+		<td style="width:250px;">&lt;-</td>
+		<td></td>
+	</tr>
 	<tr>
 		<td id="Meta8Bit"><a href="teraterm-term.html#Meta8Bit">Meta8Bit</a></td>
 		<td style="width:250px;">off</td>
diff --git a/doc/ja/html/setup/teraterm-misc.html b/doc/ja/html/setup/teraterm-misc.html
index 7025ecc7d..741060d51 100644
--- a/doc/ja/html/setup/teraterm-misc.html
+++ b/doc/ja/html/setup/teraterm-misc.html
@@ -504,5 +504,22 @@
 BracketedControlOnly=off
 </pre>
 
+<h1 id="MessageBoxPosParentRelative">メッセージボックスを親ウインドウの中央に表示する</h1>
+
+<p>
+デフォルトでは、メッセージボックスはディスプレイの中央に表示されます。<br>
+メッセージボックスを親ウインドウの中央に表示するには、[Tera Term] セクションの MessageBoxPosParentRelative 行を以下のように変更してください。<br>
+(MessageBoxPosParentRelative=onを設定しても、一部のメッセージボックスはディスプレイの中央に表示されます)
+</p>
+
+<pre>
+MessageBoxPosParentRelative=on
+</pre>
+
+<pre>
+省略時:
+MessageBoxPosParentRelative=off
+</pre>
+
 </BODY>
 </HTML>
diff --git a/doc/ja/html/setup/teraterm.html b/doc/ja/html/setup/teraterm.html
index 68d057d8c..58605c3a9 100644
--- a/doc/ja/html/setup/teraterm.html
+++ b/doc/ja/html/setup/teraterm.html
@@ -157,6 +157,7 @@
  <li><a href="teraterm-misc.html#IniAutoBackup">設定ファイルの自動バックアップ</a></li>
  <li><a href="teraterm-misc.html#BracketedSupport">ブラケットペーストのサポート</a></li>
  <li><a href="teraterm-misc.html#BracketedControlOnly">ブラケットペーストを制御文字を含む場合に限定する</a></li>
+ <li><a href="teraterm-misc.html#MessageBoxPosParentRelative">メッセージボックスを親ウインドウの中央に表示する</a></li>
 </ul>
 
 <h3>TTSSH</h3>
diff --git a/doc/ja/teraterm.hhc b/doc/ja/teraterm.hhc
index 75e06e28d..d352e64d4 100644
--- a/doc/ja/teraterm.hhc
+++ b/doc/ja/teraterm.hhc
@@ -1001,6 +1001,11 @@
 					<param name="Local" value="html\macro\command\gettitle.html">
 					<param name="ImageNumber" value="11">
 					</OBJECT>
+				<LI> <OBJECT type="text/sitemap">
+					<param name="Name" value="getttpos">
+					<param name="Local" value="html\macro\command\getttpos.html">
+					<param name="ImageNumber" value="11">
+					</OBJECT>
 				<LI> <OBJECT type="text/sitemap">
 					<param name="Name" value="kmtfinish">
 					<param name="Local" value="html\macro\command\kmtfinish.html">
diff --git a/doc/ja/teraterm.hhp b/doc/ja/teraterm.hhp
index dd55ebb2f..c46f3d2a4 100755
--- a/doc/ja/teraterm.hhp
+++ b/doc/ja/teraterm.hhp
@@ -288,6 +288,7 @@ HlpMacroCommandGetspecialfolder=html\macro\command\getspecialfolder.html
 HlpMacroCommandGettime=html\macro\command\gettime.html
 HlpMacroCommandGettitle=html\macro\command\gettitle.html
 HlpMacroCommandGetttdir=html\macro\command\getttdir.html
+HlpMacroCommandGetttpos=html\macro\command\getttpos.html
 HlpMacroCommandGetver=html\macro\command\getver.html
 HlpMacroCommandGoto=html\macro\command\goto.html
 HlpMacroCommandIfdefined=html\macro\command\ifdefined.html
@@ -331,6 +332,7 @@ HlpMacroCommandRotateright=html\macro\command\rotateright.html
 HlpMacroCommandScprecv=html\macro\command\scprecv.html
 HlpMacroCommandScpsend=html\macro\command\scpsend.html
 HlpMacroCommandSend=html\macro\command\send.html
+HlpMacroCommandSendbinary=html\macro\command\sendbinary.html
 HlpMacroCommandSendbreak=html\macro\command\sendbreak.html
 HlpMacroCommandSendbroadcast=html\macro\command\sendbroadcast.html
 HlpMacroCommandSendfile=html\macro\command\sendfile.html
@@ -339,6 +341,7 @@ HlpMacroCommandSendln=html\macro\command\sendln.html
 HlpMacroCommandSendlnbroadcast=html\macro\command\sendlnbroadcast.html
 HlpMacroCommandSendlnmulticast=html\macro\command\sendlnmulticast.html
 HlpMacroCommandSendmulticast=html\macro\command\sendmulticast.html
+HlpMacroCommandSendtext=html\macro\command\sendtext.html
 HlpMacroCommandSetdate=html\macro\command\setdate.html
 HlpMacroCommandSetdir=html\macro\command\setdir.html
 HlpMacroCommandSetdlgpos=html\macro\command\setdlgpos.html
diff --git a/installer/release/TERATERM.INI b/installer/release/TERATERM.INI
index 6874d0aa2..4580e87be 100644
--- a/installer/release/TERATERM.INI
+++ b/installer/release/TERATERM.INI
@@ -563,6 +563,9 @@ MaxComPort=256
 ; Max buffer size of OSC string
 MaxOSCBufferSize=4096
 
+; Display a MessageBox in the center of the parent window.
+MessageBoxPosParentRelative=off
+
 ; Mouse event tracking
 MouseEventTracking=on
 
diff --git a/teraterm/common/helpid.h b/teraterm/common/helpid.h
index e0dfa64d2..db78d1ca1 100644
--- a/teraterm/common/helpid.h
+++ b/teraterm/common/helpid.h
@@ -259,7 +259,7 @@
 #define HlpMacroCommandCrc32File        92139
 #define HlpMacroCommandCygConnect       92130
 #define HlpMacroCommandDelpassword      92011
-#define HlpMacroCommandDelpassword2     92219
+#define HlpMacroCommandDelpassword2     92221
 #define HlpMacroCommandDirname          92188
 #define HlpMacroCommandDirnameBox       92214
 #define HlpMacroCommandDisconnect       92012
@@ -309,11 +309,12 @@
 #define HlpMacroCommandGetipv6addr      92200
 #define HlpMacroCommandGetmodemstatus   92213
 #define HlpMacroCommandGetpassword      92046
-#define HlpMacroCommandGetpassword2     92218
+#define HlpMacroCommandGetpassword2     92220
 #define HlpMacroCommandGetspecialfolder 92195
 #define HlpMacroCommandGettime          92047
 #define HlpMacroCommandGettitle         92048
 #define HlpMacroCommandGetttdir         92140
+#define HlpMacroCommandGetttpos         92223
 #define HlpMacroCommandGetver           92133
 #define HlpMacroCommandGoto             92049
 #define HlpMacroCommandIfdefined        92115
@@ -323,7 +324,7 @@
 #define HlpMacroCommandInt2str          92053
 #define HlpMacroCommandIntdim           92150
 #define HlpMacroCommandIsPassword       92197
-#define HlpMacroCommandIsPassword2      92220
+#define HlpMacroCommandIsPassword2      92222
 #define HlpMacroCommandKmtfinish        92054
 #define HlpMacroCommandKmtget           92055
 #define HlpMacroCommandKmtrecv          92056
@@ -342,6 +343,9 @@
 #define HlpMacroCommandMakepath         92064
 #define HlpMacroCommandMessagebox       92065
 #define HlpMacroCommandMpause           92111
+#if defined(OUTPUTDEBUGSTRING_ENABLE)
+#define HlpMacroCommandOutputdebugstring 92216
+#endif
 #define HlpMacroCommandPasswordbox      92067
 #define HlpMacroCommandPause            92068
 #define HlpMacroCommandQuickvanrecv     92069
@@ -356,14 +360,16 @@
 #define HlpMacroCommandScprecv          92131
 #define HlpMacroCommandScpsend          92132
 #define HlpMacroCommandSend             92074
+#define HlpMacroCommandSendbinary       92218
 #define HlpMacroCommandSendbreak        92075
 #define HlpMacroCommandSendbroadcast    92144
 #define HlpMacroCommandSendlnbroadcast  92147
 #define HlpMacroCommandSendfile         92076
 #define HlpMacroCommandSendkcode        92077
 #define HlpMacroCommandSendln           92078
-#define HlpMacroCommandSendlnmulticast  92216
+#define HlpMacroCommandSendlnmulticast  92157
 #define HlpMacroCommandSendmulticast    92145
+#define HlpMacroCommandSendtext         92217
 #define HlpMacroCommandSetbaud          92134
 #define HlpMacroCommandSetdate          92079
 #define HlpMacroCommandSetDebug         92175
@@ -377,7 +383,7 @@
 #define HlpMacroCommandSetflowctrl      92215
 #define HlpMacroCommandSetMulticastName 92146
 #define HlpMacroCommandSetPassword      92196
-#define HlpMacroCommandSetPassword2     92217
+#define HlpMacroCommandSetPassword2     92219
 #define HlpMacroCommandSetrts           92136
 #define HlpMacroCommandSetspeed         92217
 #define HlpMacroCommandSetsync          92084
diff --git a/teraterm/common/ttddecmnd.h b/teraterm/common/ttddecmnd.h
index e53285b63..872131f1b 100644
--- a/teraterm/common/ttddecmnd.h
+++ b/teraterm/common/ttddecmnd.h
@@ -91,6 +91,7 @@
 #define CmdSendUTF8String   'a'
 #define CmdSendBinary       'b'
 #define CmdSendCompatString 'c'	// 従来の文字送信と互換, StringかBinaryか判定必要
+#define CmdGetTTPos         'd'
 
 #define LogOptBinary        1
 #define LogOptAppend        2
diff --git a/teraterm/common/ttlib.h b/teraterm/common/ttlib.h
index e99d6c2cd..ee37cbc6d 100644
--- a/teraterm/common/ttlib.h
+++ b/teraterm/common/ttlib.h
@@ -49,6 +49,8 @@ extern "C" {
 #define _Printf_format_string_
 #endif
 
+extern WORD MessageBoxPosParentRelative;
+
 BOOL GetFileNamePos(const char *PathName, int *DirLen, int *FNPos);
 BOOL GetFileNamePosU8(const char *PathName, int *DirLen, int *FNPos);
 BOOL GetFileNamePosW(const wchar_t *PathName, size_t *DirLen, size_t *FNPos);
diff --git a/teraterm/common/ttlib_static_cpp.cpp b/teraterm/common/ttlib_static_cpp.cpp
index 4e81e07d2..1cb4cc723 100644
--- a/teraterm/common/ttlib_static_cpp.cpp
+++ b/teraterm/common/ttlib_static_cpp.cpp
@@ -50,12 +50,16 @@
 #include "compat_win.h"
 #include "fileread.h"
 #include "tt-version.h"
+#include "tttypes.h"
 
 #include "ttlib.h"
 
 // for isInvalidFileNameCharW / replaceInvalidFileNameCharW
 static const wchar_t *invalidFileNameCharsW = L"\\/:*?\"<>|";
 
+// for TTMessageBoxW()
+WORD MessageBoxPosParentRelative = 0;
+
 /**
  *	MessageBoxを表示する
  *
@@ -70,6 +74,15 @@ static const wchar_t *invalidFileNameCharsW = L"\\/:*?\"<>|";
  *	info.message_key, info.message_default 両方ともNULLの場合
  *		可変引数の1つ目を書式化文字列として使用する
  */
+
+static void CALLBACK TTMessageBoxW_WinEventProc(HWINEVENTHOOK hWinEventHook, DWORD event, HWND hwnd, LONG idObject, LONG idChild, DWORD dwEventThread, DWORD dwmsEventTime)
+{
+	if ((GetWindowLongPtr(hwnd, GWL_STYLE) & WS_CHILD) == 0) {
+		CenterWindow(hwnd, GetParent(hwnd));
+		UnhookWinEvent(hWinEventHook);
+	}
+}
+
 int TTMessageBoxW(HWND hWnd, const TTMessageBoxInfoW *info, const wchar_t *UILanguageFile, ...)
 {
 	const char *section = info->section;
@@ -99,6 +112,11 @@ int TTMessageBoxW(HWND hWnd, const TTMessageBoxInfoW *info, const wchar_t *UILan
 		free(format);
 	}
 
+	if (hWnd != NULL && MessageBoxPosParentRelative == 1) {
+		SetWinEventHook(EVENT_OBJECT_CREATE, EVENT_OBJECT_CREATE, NULL,
+			&TTMessageBoxW_WinEventProc, GetCurrentProcessId(), GetCurrentThreadId(), WINEVENT_OUTOFCONTEXT);
+	}
+
 	int r = MessageBoxW(hWnd, message, title, uType);
 
 	free(title);
diff --git a/teraterm/common/tttypes.h b/teraterm/common/tttypes.h
index a22611234..644d2c9b4 100644
--- a/teraterm/common/tttypes.h
+++ b/teraterm/common/tttypes.h
@@ -616,6 +616,7 @@ struct tttset {
 	WORD BracketedControlOnly;
 	wchar_t *ViewlogEditorW;
 	wchar_t *ViewlogEditorArg;
+	WORD MessageBoxPosParentRelative;
 
 	// Experimental
 	BYTE ExperimentalTreeProprtySheetEnable;
diff --git a/teraterm/teraterm/ttdde.c b/teraterm/teraterm/ttdde.c
index 051892a9b..eafc83ff3 100644
--- a/teraterm/teraterm/ttdde.c
+++ b/teraterm/teraterm/ttdde.c
@@ -60,6 +60,7 @@
 #include "vtterm.h"
 #include "ttcstd.h"
 #include "ddelib.h"
+#include "vtdisp.h"
 
 #define ServiceName "TERATERM"
 #define ItemName "DATA"
@@ -1073,6 +1074,37 @@ static HDDEDATA AcceptExecute(HSZ TopicHSz, HDDEDATA Data)
 		}
 		break;
 
+	case CmdGetTTPos:
+		int showflag;
+		int w_x, w_y, w_width, w_height;	// ウインドウ領域
+		int c_x, c_y, c_width, c_height;	// クライアント領域
+		RECT r;
+
+		if (IsIconic(HVTWin) == TRUE) {
+		    showflag = 1;
+		} else if (IsZoomed(HVTWin) == TRUE) {
+		    showflag = 2;
+		} else if (IsWindowVisible(HVTWin) == FALSE) {
+		    showflag = 3;
+		} else {
+		    showflag = 0;
+		}
+
+		GetWindowRect(HVTWin, &r);
+		w_x      = r.left;
+		w_y      = r.top;
+		w_width	 = r.right  - r.left;
+		w_height = r.bottom - r.top;
+
+		DispGetWindowPos(&c_x, &c_y, TRUE);
+		DispGetWindowSize(&c_width, &c_height, TRUE);
+
+		_snprintf_s(ParamFileName, sizeof(ParamFileName), _TRUNCATE,
+			    "%d %d %d %d %d %d %d %d %d", showflag,
+			    w_x, w_y, w_width, w_height,
+			    c_x, c_y, c_width, c_height);
+		break;
+
 	case CmdSendBroadcast: { // 'sendbroadcast'
 		wchar_t *strW = ToWcharU8(ParamFileName);
 		if (strW != NULL) {
diff --git a/teraterm/ttpmacro/ttl.cpp b/teraterm/ttpmacro/ttl.cpp
index 7fc336ce8..0bb316778 100644
--- a/teraterm/ttpmacro/ttl.cpp
+++ b/teraterm/ttpmacro/ttl.cpp
@@ -2878,6 +2878,61 @@ static WORD TTLGetModemStatus(void)
 	return Err;
 }
 
+static WORD TTLGetTTPos(void)
+{
+	WORD Err;
+	TVarId showflag;
+	TVarId w_x, w_y, w_width, w_height;
+	TVarId c_x, c_y, c_width, c_height;
+	char Str[MaxStrLen];
+
+	Err = 0;
+	GetIntVar(&showflag, &Err); // 0:通常状態、1:最小化状態、2:最大化状態、3:非可視状態
+	GetIntVar(&w_x,      &Err); // w_x, w_y = ウインドウ領域の左上隅
+	GetIntVar(&w_y,      &Err);
+	GetIntVar(&w_width,  &Err);
+	GetIntVar(&w_height, &Err);
+	GetIntVar(&c_x,      &Err); // c_x, c_y = クライアント(テキスト)領域の左上隅
+	GetIntVar(&c_y,      &Err);
+	GetIntVar(&c_width,  &Err);
+	GetIntVar(&c_height, &Err);
+
+	if ((Err == 0) && (GetFirstChar() != 0)) {
+		Err = ErrSyntax;
+    }
+	if ((Err == 0) && (! Linked)) {
+		Err = ErrLinkFirst;
+	}
+	if (Err != 0) {
+		return Err;
+	}
+
+	Err = GetTTParam(CmdGetTTPos, Str, sizeof(Str));
+	if (Err == 0) {
+		int tmp_showflag;
+		int tmpw_x, tmpw_y, tmpw_width, tmpw_height;
+		int tmpc_x, tmpc_y, tmpc_width, tmpc_height;
+		if (sscanf_s(Str, "%d %d %d %d %d %d %d %d %d", &tmp_showflag,
+					 &tmpw_x, &tmpw_y, &tmpw_width, &tmpw_height,
+					 &tmpc_x, &tmpc_y, &tmpc_width, &tmpc_height) == 9) {
+			SetIntVal(showflag, tmp_showflag);
+			SetIntVal(w_x,      tmpw_x);
+			SetIntVal(w_y,      tmpw_y);
+			SetIntVal(w_width,  tmpw_width);
+			SetIntVal(w_height, tmpw_height);
+			SetIntVal(c_x,      tmpc_x);
+			SetIntVal(c_y,      tmpc_y);
+			SetIntVal(c_width,  tmpc_width);
+			SetIntVal(c_height, tmpc_height);
+			SetResult(0);
+		} else {
+			SetResult(-1);
+		}
+	}
+
+	return Err;
+}
+
 //
 // Tera Term のバージョン取得 & 比較
 // バージョン番号はコンパイル時に決定する。
@@ -6052,6 +6107,8 @@ static int ExecCmnd(void)
 			Err = TTLGetTitle(); break;
 		case RsvGetTTDir:
 			Err = TTLGetTTDir(); break;
+		case RsvGetTTPos:
+			Err = TTLGetTTPos(); break;
 		case RsvGetVer:
 			Err = TTLGetVer(); break;
 		case RsvGoto:
diff --git a/teraterm/ttpmacro/ttmacro.cpp b/teraterm/ttpmacro/ttmacro.cpp
index c741ef589..345a2253b 100644
--- a/teraterm/ttpmacro/ttmacro.cpp
+++ b/teraterm/ttpmacro/ttmacro.cpp
@@ -75,6 +75,8 @@ HWND GetHWND()
 
 static void init()
 {
+	wchar_t Temp[4];
+
 	HomeDirW = GetHomeDirW(hInst);
 	SetupFNameW = GetDefaultFNameW(HomeDirW, L"TERATERM.INI");
 
@@ -85,7 +87,6 @@ static void init()
 
 	// DPI Aware (高DPI対応)
 	if (pIsValidDpiAwarenessContext != NULL && pSetThreadDpiAwarenessContext != NULL) {
-		wchar_t Temp[4];
 		GetPrivateProfileStringW(L"Tera Term", L"DPIAware", NULL, Temp, _countof(Temp), SetupFNameW);
 		if (_wcsicmp(Temp, L"on") == 0) {
 			if (pIsValidDpiAwarenessContext(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2) == TRUE) {
@@ -99,6 +100,12 @@ static void init()
 	GetI18nLogfontW(L"Tera Term", L"DlgFont", &logfont, 0, SetupFNameW);
 	SetDialogFont(logfont.lfFaceName, logfont.lfHeight, logfont.lfCharSet,
 				  UILanguageFileW, "Tera Term", "DLG_SYSTEM_FONT");
+
+	// MessageBoxPosParentRelativeの取得
+	GetPrivateProfileStringW(L"Tera Term", L"MessageBoxPosParentRelative", NULL, Temp, _countof(Temp), SetupFNameW);
+	if (_wcsicmp(Temp, L"on") == 0) {
+		MessageBoxPosParentRelative = 1;
+	}
 }
 
 // TTMACRO main engine
diff --git a/teraterm/ttpmacro/ttmparse.cpp b/teraterm/ttpmacro/ttmparse.cpp
index 868b61772..0b26cb87f 100644
--- a/teraterm/ttpmacro/ttmparse.cpp
+++ b/teraterm/ttpmacro/ttmparse.cpp
@@ -281,6 +281,7 @@ BOOL CheckReservedWord(PCHAR Str, LPWORD WordId)
 		else if (_stricmp(Str,"gettime")==0) *WordId = RsvGetTime;
 		else if (_stricmp(Str,"gettitle")==0) *WordId = RsvGetTitle;
 		else if (_stricmp(Str,"getttdir")==0) *WordId = RsvGetTTDir;
+		else if (_stricmp(Str,"getttpos")==0) *WordId = RsvGetTTPos;
 		else if (_stricmp(Str,"getver")==0) *WordId = RsvGetVer;
 		else if (_stricmp(Str,"goto")==0) *WordId = RsvGoto;
 		break;
diff --git a/teraterm/ttpmacro/ttmparse.h b/teraterm/ttpmacro/ttmparse.h
index 631f1adca..a92539a4d 100644
--- a/teraterm/ttpmacro/ttmparse.h
+++ b/teraterm/ttpmacro/ttmparse.h
@@ -295,6 +295,7 @@ typedef enum {
 #define RsvGetPassword2 220
 #define RsvDelPassword2 221
 #define RsvIsPassword2  222
+#define RsvGetTTPos     223
 
 #define RsvOperator     1000
 #define RsvBNot         1001
diff --git a/teraterm/ttpset/ttset.c b/teraterm/ttpset/ttset.c
index 512727bad..66a6887bf 100644
--- a/teraterm/ttpset/ttset.c
+++ b/teraterm/ttpset/ttset.c
@@ -2072,6 +2072,10 @@ void PASCAL _ReadIniFile(const wchar_t *FName, PTTSet ts)
 	ts->BracketedSupport = GetOnOff(Section, "BracketedSupport", FName, TRUE);
 	ts->BracketedControlOnly = GetOnOff(Section, "BracketedControlOnly", FName, FALSE);
 
+	// MessageBoxの表示位置
+	ts->MessageBoxPosParentRelative = GetOnOff(Section, "MessageBoxPosParentRelative", FName, FALSE);
+	MessageBoxPosParentRelative = ts->MessageBoxPosParentRelative;
+
 	// Experimental
 	ts->ExperimentalTreeProprtySheetEnable = GetOnOff("Experimental", "TreeProprtySheet", FName, FALSE);
 }
@@ -3330,6 +3334,8 @@ void PASCAL _WriteIniFile(const wchar_t *FName, PTTSet ts)
 	WriteOnOff(Section, "BracketedSupport", FName, ts->BracketedSupport);
 	WriteOnOff(Section, "BracketedControlOnly", FName, ts->BracketedControlOnly);
 
+	// MessageBoxの表示位置
+	WriteOnOff(Section, "MessageBoxPosParentRelative", FName, ts->MessageBoxPosParentRelative);
 }
 
 void PASCAL _CopySerialList(const wchar_t *IniSrc, const wchar_t *IniDest, const wchar_t *section,
diff --git a/ttssh2/ttxssh/fwd.c b/ttssh2/ttxssh/fwd.c
index 253724dc8..b2bcd1217 100644
--- a/ttssh2/ttxssh/fwd.c
+++ b/ttssh2/ttxssh/fwd.c
@@ -1956,10 +1956,8 @@ void FWD_end(PTInstVar pvar)
 
 BOOL FWD_agent_forward_confirm(PTInstVar pvar)
 {
-	char title[MAX_UIMSG];
-	HWND cur_active = GetActiveWindow();
-
 	if (pvar->session_settings.ForwardAgentNotify) {
+		char title[MAX_UIMSG];
 		UTIL_get_lang_msg("MSG_FWD_AGENT_NOTIFY_TITLE", pvar, "Agent Forwarding");
 		strncpy_s(title, sizeof(title), pvar->UIMsg, _TRUNCATE);
 		UTIL_get_lang_msg("MSG_FWD_AGENT_NOTIFY", pvar, "Remote host access to agent");
@@ -1970,11 +1968,16 @@ BOOL FWD_agent_forward_confirm(PTInstVar pvar)
 	}
 
 	if (pvar->session_settings.ForwardAgentConfirm) {
-		UTIL_get_lang_msg("MSG_FWD_AGENT_FORWARDING_CONFIRM", pvar,
-		                  "Are you sure you want to accept agent-forwarding request?");
-		if (MessageBox(cur_active != NULL ? cur_active : pvar->NotificationWindow,
-		               pvar->UIMsg, "TTSSH",
-		               MB_YESNO | MB_ICONQUESTION | MB_DEFBUTTON2) == IDYES) {
+		static const TTMessageBoxInfoW info = {
+			"TTSSH",
+			NULL, L"TTSSH",
+			"MSG_FWD_AGENT_FORWARDING_CONFIRM",
+			L"Are you sure you want to accept agent-forwarding request?",
+			MB_YESNO | MB_ICONQUESTION | MB_DEFBUTTON2
+		};
+		HWND cur_active = GetActiveWindow();
+		HWND parent_hwnd = cur_active != NULL ? cur_active : pvar->NotificationWindow;
+		if (TTMessageBoxW(parent_hwnd, &info, pvar->ts->UILanguageFileW) == IDYES) {
 			return TRUE;
 		}
 		else {
diff --git a/ttssh2/ttxssh/ssh.c b/ttssh2/ttxssh/ssh.c
index 5cf089784..ee0cef512 100644
--- a/ttssh2/ttxssh/ssh.c
+++ b/ttssh2/ttxssh/ssh.c
@@ -4271,7 +4271,7 @@ int SSH_scp_transaction(PTInstVar pvar, const char *sendfile, const char *dstfil
 			wchar_t *err_str;
 			hFormatMessageW(error, &err_str);
 			wchar_t *fname = ToWcharU8(sendfile);
-			TTMessageBoxW(NULL, &info, pvar->ts->UILanguageFileW, err_str, fname);
+			TTMessageBoxW(pvar->cv->HWin, &info, pvar->ts->UILanguageFileW, err_str, fname);
 			free(fname);
 			free(err_str);
 			goto error;
@@ -4324,7 +4324,7 @@ int SSH_scp_transaction(PTInstVar pvar, const char *sendfile, const char *dstfil
 					MB_OK | MB_ICONERROR
 				};
 				wchar_t *fname = ToWcharU8(c->scp.localfilefull);
-				TTMessageBoxW(NULL, &info, pvar->ts->UILanguageFileW, fname);
+				TTMessageBoxW(pvar->cv->HWin, &info, pvar->ts->UILanguageFileW, fname);
 				free(fname);
 				goto error;
 			}
@@ -4335,7 +4335,7 @@ int SSH_scp_transaction(PTInstVar pvar, const char *sendfile, const char *dstfil
 				MB_YESNO | MB_ICONQUESTION
 			};
 			wchar_t *fname = ToWcharU8(c->scp.localfilefull);
-			dlgresult = TTMessageBoxW(NULL, &info, pvar->ts->UILanguageFileW, fname);
+			dlgresult = TTMessageBoxW(pvar->cv->HWin, &info, pvar->ts->UILanguageFileW, fname);
 			free(fname);
 			if (dlgresult == IDNO) {
 				goto error;
@@ -4354,7 +4354,7 @@ int SSH_scp_transaction(PTInstVar pvar, const char *sendfile, const char *dstfil
 			wchar_t *err_str;
 			hFormatMessageW(error, &err_str);
 			wchar_t *fname = ToWcharU8(c->scp.localfilefull);
-			TTMessageBoxW(NULL, &info, pvar->ts->UILanguageFileW, err_str, fname);
+			TTMessageBoxW(pvar->cv->HWin, &info, pvar->ts->UILanguageFileW, err_str, fname);
 			free(fname);
 			free(err_str);
 			goto error;
@@ -8922,12 +8922,14 @@ static void SSH2_scp_response(PTInstVar pvar, Channel_t *c, unsigned char *data,
 			//ssh2_channel_delete(c);  // free channel
 			//ssh2_channel_send_close(pvar, c);
 		}
-
-		wchar_t uimsgW[MAX_UIMSG];
-		UTIL_get_lang_msgW("MSG_SSH_SCP_ERROR_TITLE", pvar,
-						   L"TTSSH: SCP error", uimsgW);
+		static const TTMessageBoxInfoW info = {
+				"TTSSH",
+				"MSG_SSH_SCP_ERROR_TITLE", L"TTSSH: SCP error",
+				"MSG_SSH_SCP_ERROR_MISC", L"%s",
+				MB_OK | MB_ICONEXCLAMATION
+		};
 		wchar_t *msgW = ToWcharU8(msg);
-		MessageBoxW(pvar->cv->HWin, msgW, uimsgW, MB_OK | MB_ICONEXCLAMATION);
+		TTMessageBoxW(pvar->cv->HWin, &info, pvar->ts->UILanguageFileW, msgW);
 		free(msgW);
 	}
 }
diff --git a/ttssh2/ttxssh/ttxssh.c b/ttssh2/ttxssh/ttxssh.c
index cdce97163..ea1e1c989 100644
--- a/ttssh2/ttxssh/ttxssh.c
+++ b/ttssh2/ttxssh/ttxssh.c
@@ -1406,6 +1406,7 @@ static void PASCAL TTXReadINIFile(const wchar_t *fileName, PTTSet ts)
 	pvar->settings = *pvar->ts_SSH;
 	logputs(LOG_LEVEL_VERBOSE, "Reading INI file");
 	FWDUI_load_settings(pvar);
+	MessageBoxPosParentRelative = ts->MessageBoxPosParentRelative;
 }
 
 static void PASCAL TTXWriteINIFile(const wchar_t *fileName, PTTSet ts)
