Add note on absolute links

docs/userGuide/syntax/includes.md

@@ -56,6 +56,15 @@ When setting the `id` of a fragment, be careful not to clash with heading anchor
 </box>
 
 <include src="panels.md#script_and_styles_warning"></include>
+<div id="baseUrl-warning">
+<box type="warning" header="Add `{{ '{{ baseUrl }}' }}` to local URLs to always point to the same target!">
+
+For links within `<include>` to always point to the same target, make it an absolute link with `{{ '{{ baseUrl }}' }}` included.  
+
+For example, if file `folder1/file1.md` contains an absolute link `{{ '{{ [link]({{ baseUrl }}/folder1/target.html) }} ' }}` when `file1.md` is included in `folder2/file2.md`, the link will point to `folder1/target1.html`. Keep this in mind when putting content with links within `<include>`.
+</box>
+</div>
+
 
 <include src="tip.md" boilerplate >
 <span id="tip_body">

docs/userGuide/syntax/links.md

@@ -99,6 +99,8 @@ To ensure that links in the <code>_markbind/</code> folder work correctly across
 {% endraw %}
 </div>
 
+<include src="includes.md#baseUrl-warning"/>
+
 ****Relative paths****
 
 <div class="indented">

docs/userGuide/syntax/panels.md

@@ -167,6 +167,8 @@ To safeguard against unintended consequences, consider directly incorporating th
 </variable>
 </include>
 
+<include src="includes.md#baseUrl-warning"/>
+
 **If `preload` attribute is provided, the panel body will load the HTML when the page renders instead of after being expanded.**
 
 <include src="codeAndOutput.md" boilerplate >

docs/userGuide/syntax/popovers.md

@@ -71,6 +71,8 @@
 </variable>
 </include>
 
+<include src="includes.md#baseUrl-warning"/>
+
 **Using trigger for Popover:**<br>
 
 <include src="codeAndOutput.md" boilerplate >

docs/userGuide/troubleshooting.md

@@ -93,4 +93,15 @@ You could signpost Markdown either by:
 <box> **This will be rendered as plain text**</box>
 </variable>
 </include>
-</panel>
+</panel>
+
+##### Content with local links not working when included with `<include>`
+
+If you notice that relative links in a page pointing to another page no longer works after adding it into a page via `<include>`, it may be because the relative link no longer points to the correct address in the new page with `<includes>`. 
+
+To solve this, change the relative URL into an **absolute** URL by adding `{{ '{{ baseUrl }}' }}`. This will ensure that the link will always point to the same address regardless of the page it is included in.
+
+###### Example: Adding `{{ '{{ baseUrl }}' }}` to make absolute URLs
+
+If file `folder1/file1.md` contains an absolute link `{{ '{{ [link]({{ baseUrl }}/folder1/target.html) }} ' }}`, when `file1.md` is included in `folder2/file2.md`, the link will point to `folder1/target1.html` even if the target is not in the same directory as `file2.md`.
+