Use the correct old screen to shift panels to new screen
Review Request #125694 - Created Oct. 18, 2015 and submitted
To move the panels of screen [i] to the next screen, we should query for the panels of DesktopView [i], not of DesktopView [i + 1]. Otherwise the panels aren't shifted to the new screen. Thus QT shifted the panels itself, but hid them afterwards. Besides the panels were not visible, it raised an assert in screenInvariants().
The panel now gets shifted correctly when unplugging a screen. I tested it only with 2 screens, i'm not sure whether this loop works with more than 2 screens, this needs more investigation..