Dual Monitor Setup causes trouble with menus and popups

Hello,

I have a dual monitor layout. On the left I have a 1680x1050 monitor, on the right there's a 2560x1440 monitor. They are not aligned at the top but at the bottom. So the left monitor is 390 pixels below the right one.

When I open a Qt Application (it does not matter which one), menus and popups are displayed at the wrong position (too far below the mouse cursor) when triggered within the first 390 pixels in y-direction of the right monitor.

For example, if I trigger the menu at (2000, 200), the menu is displayed at (2000, 390). When I trigger it at (2000, 100) it is displayed at (2000, 390) as well.

On the left monitor there are no issues. If I align both monitors on top, there's no problem either. (See Issue 1.1, 1.2)

 Actually, this bug is very old and known for at least version 4.4

https://bugreports.qt.io/browse/QTBUG-2748

I experienced it under Gnome, Unity, Mate and KDE. I cannot tell if this bug appears in Windows, too. Sorry for this.

Thanks a lot in advance,

Lucio

Edit:

I just tried out what happens, when the left monitor is a lot of higher than the right one. On the left monitor, the menus do not appear at all, on the right one, they are very very long. I am going to attach some screenshots (See Issue 2.1, 2.2)

Edit 2: I guess, this is a duplicate of this bug. Maybe they can be merged

https://bugreports.qt.io/browse/QTBUG-29278