QMdiArea::tileSubWindows causes application window reposition

If a windows tiling is performed in the mdi area the application main window is repositioned in the screen.

The problem is also visible in the mdi example:
Open the mdi example, create a new file, tile windows (Window menu|Tile)

Similarly
Open the mdi example, expand the application (green plus icon on the top left corner), create a new file, tile windows (Window menu|Tile)