When I advance in a technology during gameplay, I get an error that reads:

Python exception
Traceback (most recent call last)
File "CvScreensInterface", line 749, in update
Attribute error: 'NoneType' object has no attribute 'update'.

When the window appears, I can't play the game anymore. I try to close it, but it will not disappear.

It's a bit frustrating. :sad: