[REG: 5.10.1->5.11.0-alpha] Mouse events not observed when Super (Windows) key is held down.

Mouse events are not observed in the event handler if a Super (Windows) key is currently pressed. This does not happen with any other keys. 
The issue happens in CentOS7 and Ubuntu 20.04 with GNOME or GNOME classic. The issue is not observed with the MATE desktop environment.

The issue does NOT happen with Qt 5.9.6.

The example app does a keyboard hook to intercept the Super key press, but still the mouse press is not observed.

To reproduce the issue:
1) Run the attached example on Ubuntu or CentOS7 GNOME desktop environment. A window will be shown. When keys or mouse buttons are pressed, this information is logged to the application output window.
2) Press a mouse button. Observe the mouse button press/release is logged.
4) Press and hold the Super ( Windows ) key. Then press any mouse button. Observe that no mouse button event is logged.