Mine used to do that...but is it a big deal? I'm not sure what causes it, but I've dealt with it before and it got sorted out by itself.
Not really a big deal, as I can see all that stuff on Firefox, just annoying. I can wait for a Steam update and maybe it will go back to normal, just wondering if there was a fix (it's and OCD thing for me, something on my comp not working LOL)