Monitor-spanning windows: unexpected size of OS pop-ups (context menus, tooltips)

[HeikoKlare]

General Description

When having a workbench window spanning multiple monitors with different scale values, the window shell is scaled according to the monitor containing more than 50% of the shell space.
Pop-up elements provided by the OS, like context menus and tooltips, scale according to their monitor and not the shell they belong to. Thus, on the monitor containing less than 50% of the workbench window shell space, those elements will look improperly sizes, as their scaling is different from the one of the shell.

Cases

All cases may be reproduced with two monitors at different scale values, a workbench window spanning both of them and opening the according kinds of controls on the monitor to which the shells scale does not fit.

Context menus

Original issue: #177

Tooltips

Original issue: #175