Not just you, same observation here.
Found the new avitab clickspot on the left, but screen stays black. Interestingly, that square button does something, it resets the avitab screen to main menu (watch it in the regular avitab window), so at least something is happening, which means connection to avitab itself exists. I tried to find some clickspot on the edges of the screen to turn it on, like seen in other aircraft with avitab integration, but no luck so far.
Standalone avitab v0.4.6.window works fine. Pre-1.2 also no problems worked.