Event Filter Mouse Press/Release Event not called

Hi,
I'm using an event filter for a custom window without border, it's used to have the MoveHover event for the resize cursor and know the area of the mouse to set the good resize mode.
All works good for this part but then it's needed to know the mouse press event/mouse release event to resize the window but the events are not called in the event filter.
Why it's not called ? How solve this issue ?
Thanks for the help

Does your custom window have child widgets inside it? It is possible that they are receiving and handling the mouse events and not passing them up to the parent.

Yes basically it's a main window with a tab widget as center widget and the event filter is installed on the main window.

I've added a widget which act as border, it's the top level widget and the tab widget is inside it into one layout but the event is still not called, something has to be disabled on this widget to have the correct mouse event called on the parent ?
Thanks