Hi,

I had time to investigate a little further.
As I noticed before if I force a resize of the QWidget containing the QTabWidget, the new row will appear.

I also forgot to say that I use an item delegate for the QTreeView. My first thought was that I did not paint anything or the QPainter was invalid the first time I use it. But unfortunately, this is not the case. It seems to paint everything but nothing appear on screen.

If anybody has a clue, it would relieve me!

Regards,
Lionel