I was tooling around looking at a couple posts I was interested in. Then I picked the icon to show my preferences and I got that error.
I had another tab open on this site and went to it to get to this topic. I started typing and thought I put attach an image so I went back to the other tab and did the same but it didn't give me the error. So it seems like it happens when I spend a little bit of time on a page without clicking something? I was reading a little lengthy post.
