Cannot type in visual editor after upgrade to 2.8

Hi,

I upgraded two of my blogs to 2.8 over the weekend, and now, when I try to type in the Visual Editor, I get nothing but a row of red dots. When I hit the HTML tab, however, everything I’ve typed in is there. When I go back to the Visual tab, then I can type again with no problems. I’m glad I can still enter new posts, but it’s just kind of a pain if this is the way I’ll have to end up typing anything from here on out. Does anyone have any ideas about what could be wrong? I have no actual site problems, this is strictly in the admin/Dashboard/Visual Editor.