DockWidgets with custom title bar resize when moving between screens if AA_EnableHighDpiScaling is set

1. Have two 4K screens in Extend mode
2. Extract the attached project and build and run (modified DockWidget example project)
3. Undock the dockwidget then drag it across to the other screen
4. The widget resizes, sometimes dramatically, as it crosses the screen boundary.

It's not always consistent how much it changes, or if it gets bigger or smaller. I have had crashes caused by this as the widget got too big. The last crash seemed to be a result of the widget having the following size {width = 12933, height = 49152}.

This behaviour only seems to occur when the DockWidget has a custom title bar widget set, and the AA_EnableHighDpiScaling set.