Quick update... we found out that setting the zoom manually will make the tabs reappear.
So I tryed to write a simple macro to reset the zoom to 100% on all sheets and it does work on 7.52 but the it doesn't work on the 9.00 SR3 plugin.
I tryed setting the zoom factor to both 1 and 100. 7.52 values range from 1 to 100 and QV9 seems now 0.1 to 1.
sp.ZoomFactor = 1
So we are still stuck..