Additionally:
When I go to Control, Operators, or Variables, Snap! crashes.
BeetleBlocks has the same problem, but without crashing.
This only happens in the offline version.
Did you delete any files?
No, I just got 6.9.1, and it was happening on 6.9.0 too. Also, it only started happening today. I think it might be a Chrome update, but I'm not sure.
So what did you do to make this happen?
I'm not sure. I was making something, and I wanted to do some testing, so I opened up a new tab of Snap! and I suddenly got the bug.
Oh. It doesn't count as a Snap! bug if you break it by messing with its user interface in Javascript.
But with what I was making which had
as the only JS function block, that shouldn't have affected further times opening Snap!, or even BeetleBlocks. Plus, I made that today in 6.9.0, and only after that did I realize that 6.9.1 had come out.
Check again by download the latest version of Snap ! If it happens again, probably means, files are broken.
That's true. But you're the only one reporting this problem, so I'm pretty sure that something you did triggered it.
That has happened to me too!
I get the same problem when opening projects and sometimes making new ones.
in offline editor?
6.9.1 is the latest version, and that's the version I currently have.
In others versions, this bug show again?
In 6.9.0 and 6.9.1. Those are the only offline versions of Snap! I have. But, again, it's also happening on my offline version of BeetleBlocks.
This has happend to me too.
For some reason, asterisks don't work for italics unless the whole italicized text with the asterisks are surrounded by spaces, so I use HTML tags now, i.e. Snap<i>!</i>.
Offline? No online.
How offline
so it get problem- bigg 
I don't understand what you're saying.