Menu clicks/mouse interaction broken

I can NOT use the mouse to navigate the in-game menu (Inventory, Player, Quest log, etc; same goes for trading and other in-game menus.
After analyzing the weirdness, it seems that all of my clicks cycle through tabs.
Video of this weirdness happening

Am I the only one?

This was the case ever since I installed the game (GOG version, updated to 1.7.2.1010)

I had “cycle tabs” unset in my key bindings (because I’m a big boy and I’m using a PC. This usually means leveraging the mouse to navigate menus); now I tried setting it to something out of the way - but I can’t save my key bindings now, because the game thinks “there’s a conflict between controls!”

Ideas, anyone?

I had similar issue on Steam. It went away by itself somehow. So just restart game, load older save and then try new one.

Well…
After I (re)started the game again today, the issue with the key binding was gone.
And after I set “Cycle Tabs” to some key, the mousing issue was gone.

Preliminary conclusion:
Having Cycle Tabs unset results in mouse interaction breaking due to behind-the-scenes mapping of the mouse buttons to Cycle Tabs
Needs fix, but simply assigning a key works around the issue.