Problem with using raise function on QMainWindow

Hello, I have problem to bring to top main window. Here is the satiation:
1. I have center widget and three docking widgets
2. The problems appears when all docking widgets are floating.
3. When I click on main window, it stays under the overlapping docking widget.

What did I try:
1. implement focusInEvent in main window and call raise function of the main window.
2. call lower () of each overlapping docking widget
3. call stackUnder of the docking widget with mainwindow as a parameter

Nothing works. What else can I try?
I searched the Forum and could not find info that could help me. May be I am using wrong keywords?
Thanks in advance

The main window will never be on top of any of its dock widgets. Child windows are always on top of their parents. The only thing you can to is to "deparent" those dock widgets, but then you won't be able to dock them back.