Earlier quoted context omitted.
Ugh, I do this with Notepad++ too, and I know it's terrible. But it's just so.... automatic. I tell myself that nothing in there is truly critical, but I've also had a few instances of being pretty pleased to be able to "find in all open documents" and recover a bit history of what I was doing, or URLs for some research, or whatever.
I use Notepad++ like this too. But I try to use its split pane feature to keep all my scratch txt files out of the way of whatever project files I need open.
We started using rider at work and I already have made like 20 scratch files in under a week. It may become a problem soon.