Go to Tools - VSdocman menu or press VSdocman button on standard toolbar. VSdocman dialog appears, select Options pane. Set Comment Editor - Editor Window page.
This dialog allows you to set comment editor appearance.
Show comment editor as modal dialog
Editor will open as a modal dialog.
Show comment editor as modeless tool window
Editor will open as a modeless VS tool window. You can continue to work with IDE while the editor is open. You can dock or float that window or make it a tabbed document. It will behave exactly as other VS tool windows, e.g. Solution Explorer.
The following settings apply to modeless editor.
Automatically apply changes ...
When this option is checked, you don't need to press Apply button to apply changes from Comment editor to XML comments. When the editor looses focus or is closed, changes are automatically applied. This avoids situation when you have editor and source code window opened side by side and you forget to press Apply when leaving editor. On the other hand, it will also apply changes you made in editor but don't want them to apply. In such case you must undo in source code window.
Automatically update content of the comment editor ...
When this option is checked, the content in Comment editor will be automatically updated according to a currently active code element in a source code window. So your caret position in a code window is automatically reflected without a need of moving focus from source code to the Comment editor.