Scaling problem if flag aero snap is disabled about kddockwidgets

[iamsergio]

reproduced the problem with Aero enabled, it happens when:

• the floating window is in between screens when the drag starts
• or, if you detach a docked widget and drag it all the way to a second screen

I have a WIP to fix it, but needs more polish

[iamsergio]

I think I rather make aero-snap unconditional, to make Windows handle the resizing and the screen-changes, as Qt has bugs when doing it manually.

Any problem with aero-snap, besides issue #46 ?

[tlaemmlein]

Unfortunately I have to report that even with "aerosnap" the scaling problem is not completely eliminated. I can reproduce the problem with by sliding the DockWidget back and forth on both screens several times.
Qt-Version: 15.5.1
OS: Windows 10
In the animation I cut the movements to go faster to the problem:

The code is based on 6a46744

[tlaemmlein]

And also in our large applications the scaling problem is always there. The problem occurs with the first movement. Regardless of whether aero-snap is on or off.