Neither do I.
Then delete your post please.
Hide primitives option
That fixes but why does it happen in the first place without us pressing hide?
I think, you did it by accident- haven't even seen it 
what if you scroll up. I see that the scroll bar is close to the bottom.
that's weird. I'm gonna download snap, and see if I can reproduce it.
It could be that I was making a mod of Snap! called SnapIO, with the entire right side of the screen as a text editor, and you could write to it and read from it in your program.
I checked the Chrome Developer Tools, and it said that my regular Snap! was getting things from the folder with SnapIO stuff.
yeah, that could be it. Try a clean download. I wasn't able to reproduce it, so...
Getting a fresh download...
Edit: It still doesn't work. I'll just have to use the online version for now.
(5 months later)
I found out that the problem isn't Snap!, but that
It wasn't writing the Snap! files right.
After 5 months... time is needed to find cause of error for some things 
What about the other people who have experienced it?
IDK what you'll have to do. It's possible this:
might help you.
(earthrulerr fixed it by that.)