In some cases QToolBar creates a child window (a child borderless NSWindow)
placed on top of the toolbar's main window. As a result it's not possible
to drag this main window using its toolbar - the window "jumps" on the screen.
The reason is quite subtle - QNSView -handleMouseEvent: uses
[NSEvent mouseLocation] and this location is invalid:
- we have an NSWindow (parent)
- we have a child NSWindow ([parent addChildWindow:child ....]
- we handle drag event in a child window
- we move a parent window as a result of drag event
- Cocoa also moves a child window for us
- when handling the next drag event, location [NSEvent mouseLocation]
differs from the real event's location.
Task-number: QTBUG-40106
Change-Id: Ic68cb92ab4233a1e0746b478820c1e33fd37a462
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>
ae5f3df59b