I have had issues too, and they seem to be worse since the latest update to include video. I can type in the text field, but it seems to have a hard time recognizing where my cursor is or what text is highlighted. Often I can select to make highlighted text bold, while the 'bold' icon shows it's engaged, the text is not bold. The same goes for the 'quotation' option. It would either format all the text in the window in 'quotation' mode, or everything beyond the cursor. Other times the icons will freeze all together, forcing me to exit and get back in.
I've tried in both Firefox and IE8.