When putting a QWindow into a widget container and then adding that to a QMdiArea it can cause problems with stacking. This is because of the fact that the widget container now has a native handle and this is contributing to the problem. In the example attached there is another sub window that has always on top which is appearing correctly, but does not respond to input.

To reproduce with the attached example, do:

• Go to Major menu and choose Major SubWindow 2
• Go to Minor menu and choose Minor SubWindow 1
• Go to Major menu and choose Major SubWindow 1
• Try to interact with the Minor SubWindow which is still visible and nothing goes through