Put a widget in the MDI tabs bar

[Paddle]

In FreeCAD we use a MDI area for the main 3dView. Tabs (located at the bottom) correspond to documents.
Under this tab bar we also have a status bar. Which has a status message and two buttons.
It currently looks like so :

We have a feature request to improve the UI, to merge these two bars like so :

I am not sure how to do this. I guess I could draw the widget on top of the MDI area. But then the there're a lot of tabs, they will end up under the widget and will be hidden / not accessible.
Any suggestion?

Thanks !

[Paddle]

Oh it appears there's a 'TabWidget' functionality that may be just what we need :
https://forum.qt.io/topic/145522/how-to-display-tab-widget-corner-widget-on-the-left-right-side/2

[Paddle]

In fact I was wrong, the linked topic is about QTabWidget not QTabBar

Anyone one know how I can do what is described ? ie adding a widget to the qtabbar.
Thanks