Impess Slide pane "dock" problem drives me crazy!

Hello,
A few months back I un-docked completely by accident the the Slide pane. From that day every time I start Impress the visibility and/or docking status of the Slide Pane is completely random! I can start Impress and have the Slide Pane docked, or start with the Slide Pane NOT docked.

Most often though, I open the a presentation and the Slide Pane is not even visible. In that case, usually, I have to enable the Slide pane from the menu, deselect it (because selecting it does nothing) and select it again!

To me this sounds like a bug, but before going there; Is there any option that I could check in the configuration files?
If so, in which file and which option?

Same problem here, I couldn’t find any setting to put back the slide plane.

Then I found the solution here:
https://wiki.openoffice.org/wiki/Documentation/FAQ/Impress/How_can_I_redock_the_slide_pane

Ctrl + double click the area of the “Slides” text

Ctrl + double click is the “button” to undock and redock the slide pane. This function definitely deserves a GUI button.
About showing/hiding slide pane, the checkbox is at View > Slide Pane

This doesn’t work for me. I have no idea what I did that undocked the Slide Pane, but would like it back in it’s place. The show hide button is gone and the Slide pane is free floating. Windows 10 and Libre Office 7.5. I can see how undocked might be useful for some, but there should definitely be an obvious way to RE DOCK it. Any help would be appreciated.