Tried to save while tabbed out with task manager open in front of the screen and this error popped up. I had saved the game beforehand, so I didn't lose anything, but still startled me a bit. Assuming that it was caused by the fact I was tabbed out due to what the message came back as. This happened in 0.8.0, as I've yet to update to newer versions, so I have no idea if this still happens or not. No idea if there's a fix, nor is it really a major issue due to how unlikely it is to get. I just wanted to put it here incase it's of any value.

I think it might also happen with any window but this was with task manager when It happened. I've not tested any others. That's weird though, I might try it again to see if it was just a one-time thing or if it's repeatable. My 8.0 version was ported over from my broken old pc so that may be part of the reason though, but it runs fine. I reset all data for it ages ago too. No idea.