diff --git a/doc/cascadia/profiles.schema.json b/doc/cascadia/profiles.schema.json
index 9d5bd545686..fc300a49499 100644
--- a/doc/cascadia/profiles.schema.json
+++ b/doc/cascadia/profiles.schema.json
@@ -1348,7 +1348,7 @@
       "properties": {
         "acrylicOpacity": {
           "default": 0.5,
-          "description": "When useAcrylic is set to true, it sets the transparency of the window for the profile. Accepts floating point values from 0-1 (default 0.5).",
+          "description": "[deprecated] Please use `opacity` instead.",
           "maximum": 1,
           "minimum": 0,
           "type": "number"
@@ -1561,6 +1561,14 @@
           "minLength": 1,
           "type": "string"
         },
+
+        "opacity": {
+          "default": 100,
+          "description": "Sets the opacity of the window for the profile. Accepts values from 0-100. Defaults to 50 when useAcrylic is set to true.",
+          "maximum": 100,
+          "minimum": 0,
+          "type": "number"
+        },
         "padding": {
           "default": "8, 8, 8, 8",
           "description": "Sets the padding around the text within the window. Can have three different formats:\n -\"#\" sets the same padding for all sides \n -\"#, #\" sets the same padding for left-right and top-bottom\n -\"#, #, #, #\" sets the padding individually for left, top, right, and bottom.",
diff --git a/src/cascadia/TerminalControl/TermControl.cpp b/src/cascadia/TerminalControl/TermControl.cpp
index 2f80c0a2dcb..e08fcdb18aa 100644
--- a/src/cascadia/TerminalControl/TermControl.cpp
+++ b/src/cascadia/TerminalControl/TermControl.cpp
@@ -495,10 +495,9 @@ namespace winrt::Microsoft::Terminal::Control::implementation
             }
             else if (auto solidColor = RootGrid().Background().try_as<Media::SolidColorBrush>())
             {
-                auto originalOpacity = solidColor.Opacity();
+                const auto originalOpacity = solidColor.Opacity();
                 solidColor.Color(bg);
                 solidColor.Opacity(originalOpacity);
-                // solidColor.Color(til::color{bg.r, bg.g, bg.b, base::saturated_cast<uint8_t>(255 * originalOpacity)})
             }
         }
     }
diff --git a/src/cascadia/TerminalSettingsModel/TerminalSettings.cpp b/src/cascadia/TerminalSettingsModel/TerminalSettings.cpp
index 9478ebecdef..e52c250d1cb 100644
--- a/src/cascadia/TerminalSettingsModel/TerminalSettings.cpp
+++ b/src/cascadia/TerminalSettingsModel/TerminalSettings.cpp
@@ -202,7 +202,15 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         _IntenseIsBold = WI_IsFlagSet(appearance.IntenseTextStyle(), Microsoft::Terminal::Settings::Model::IntenseStyle::Bold);
         _IntenseIsBright = WI_IsFlagSet(appearance.IntenseTextStyle(), Microsoft::Terminal::Settings::Model::IntenseStyle::Bright);
 
-        _Opacity = appearance.Opacity();
+        // If the user set an opacity, then just use that. Otherwise, change the
+        // default value based off of whether useAcrylic was set or not. If they
+        // want acrylic, then default to 50%. Otherwise, default to 100% (fully
+        // opaque)
+        _Opacity = appearance.HasOpacity() ?
+                       appearance.Opacity() :
+                       UseAcrylic() ?
+                       .5 :
+                       1.0;
     }
 
     // Method Description:
diff --git a/src/cascadia/WindowsTerminal/NonClientIslandWindow.cpp b/src/cascadia/WindowsTerminal/NonClientIslandWindow.cpp
index face7082867..75ef888eb0a 100644
--- a/src/cascadia/WindowsTerminal/NonClientIslandWindow.cpp
+++ b/src/cascadia/WindowsTerminal/NonClientIslandWindow.cpp
@@ -687,6 +687,11 @@ void NonClientIslandWindow::_UpdateFrameMargins() const noexcept
 {
     MARGINS margins = { 0, 0, 0, 0 };
 
+    // GH#603: When we're in Focus Mode, hide the titlebar, by setting it to a single
+    // pixel tall. Otherwise, the titlebar will be visible underneath controls with
+    // vintage opacity set.
+    //
+    // We can't set it to all 0's unfortunately.
     if (_borderless)
     {
         margins.cyTopHeight = 1;
@@ -900,14 +905,8 @@ void NonClientIslandWindow::_SetIsBorderless(const bool borderlessEnabled)
         _titlebar.Visibility(_IsTitlebarVisible() ? Visibility::Visible : Visibility::Collapsed);
     }
 
-    // These are all useless.
-    // auto windowStyle = GetWindowLongW(GetHandle(), GWL_STYLE);
-    // WI_ClearAllFlags(windowStyle, WS_OVERLAPPEDWINDOW);
-    // WI_SetFlag(windowStyle, WS_SIZEBOX);
-    // // WI_SetFlag(windowStyle, WS_BORDER);
-    // WI_SetFlag(windowStyle, WS_POPUP);
-    // SetWindowLongWHelper(GetHandle(), GWL_STYLE, windowStyle);
-
+    // Update the margins when entering/leaving focus mode, so we can prevent
+    // the titlebar from showing through transparent terminal controls
     _UpdateFrameMargins();
 
     // GH#4224 - When the auto-hide taskbar setting is enabled, then we don't