Dragging the main window over the top edge of the screen sets wrong window position

• Start attached project
• Put the mouse pointer to the toolbar near the Print button (the toolbar part of the unified title and toolbar)
• Drag window to the top over the screen edge (unified_toolbar_drag_direction.png)

The application prints the position of the window and global coordinates of the (0,0) point on this window.

• Stop when the Y coordinate becomes negative.
• Click the Print button - it outputs the same coordinates.

Now the position of the window is incorrect, global coordinates obtained with mapToGlobal are incorrect as well.

• Put the mouse pointer to the title part of the unified title and toolbar
• Drag to the top - the coordinates are positive and correct

It is easier to reproduce it with an MBP trackpad, but also reproducible with an ordinary mouse.

In our app, we use mapToGlobal to determine the position for the popup window, and it is incorrect in such circumstances.