It sure is a strange error, I wonder if it was triggered by me, shutting Ctrlr down while the midi monitor window running on my second video monitor, because I remember that Ctrlr crashed on me a couple of times last night when I was shutting it down, but I can not be 100% sure that the midi monitor problem arose just after that, since I did not try to use it immediately after. It this was the case, I would expect that clean re-install would fix it.
