Weird interference with the LM main menu button when mate-terminal is maximized

[yellowfinch]

I never had this problem up to and including LM 19.3. It started on my main system after the fresh install of 20.3 and it persists after the in-place updates to 21 and 21.2. (Version 1.26.0 of mate-terminal and version 6.1.7 of mintmenu.)

The scenario is thus:

• I’m using mate-terminal in a maximized window.

• I need to launch some other app, so I press the super-key. (Or click on the mintMenu button; the result is the same.)

• Result: the menu does not open. But the terminal window loses the focus. I suspect that the focus moves to mint-menu itself because pressing the super-key again (or clicking on the menu button) moves the focus back to the terminal window. However, pressing the space bar at that point doesn’t trigger the menu as it probably would if it really had focus. And there are no other visible clues aside for the terminal window’s title bar indicating that it has the focus or not. (Per my theme.)

But...

On a test machine, with all the same versions of everything, this symptom does not exist! Pressing the super-key always opens the mintMenu as expected.

Both systems use « Marco + composition ».

The only difference is that the test machine got LM 21.1 as a fresh install. It never exhibited the symptom, and the in-place update to 21.2 didn’t introduce the symptom either.

Among all the apps and system utilities I use, mate-terminal is the only one that causes this symptom.

What could it be?