Currently, when you hover over a text in the document with the mouse (for example, the CMake "SET" command), a documentation popup appears. You can scroll in the popup as you like. But when you go back with the mouse to continue editing your document, the popup disappears and you can not use the documentation to continue writing code. It would be nice to have a way to make a popup persist until you close it. The button could look like a little pin, which you can activate to make the window stay until you close it manually. Reproducible: Didn't try
Note: You can have a persistent view of the CMake documentation in the documentation tool view. It'd be still useful to maybe have that view opened by clicking on some button in the inline documentation widget. (Just as for Qt classes with 'Show documentation for X'.)