The video did not help on my problem, but it is very interesting nontheless. Thanks!
I started TripleA again and a "Done" button appeared where none was the last time. So I guess I experienced a bug. There was also a slight difference on the combat report sub-windows of AI-v-AI fights: There was a button now to click the window away. That wasn't there, too, last time. So I really guess I witnessed a bug. (Edit: Or some weird "feature" that I didn't ask for...?)