sorry that I cannot attach a dxdiag or gamelog, I didn’t think about saving those after the hangup but it should be a very reproducible error.
Essentially, I had a hunt-something quest and was about to engage the mob I was supposed to kill. Since my figure was still a half-step away, I realised I wanted to put a brother in reserve and pressed the “c” button to open the company screen. At the same time, my party must have reached the mob because I could see that the event/ fight window popped up in the background. Now I could still do things in the company menu, but couldn’t close it any longer (I suppose the interface gets locked once you enter a fight). I also couldn’t get into the fight as I’m supposed to press the respective button in the event windows, which was blocked by the company window I couldn’t close.
All keyboard input was still being directed to the company screen. I couldn’t get to the game menu either, so the only thing that helped was to close the game and start it again.
Hope the error description is clear, let me know if you want more details. I can also try to reproduce it in case you want to see a screenshot.