Firefox 4.0 won't let me chat in Zoho Projects

I installed Firefox 4.0 this morning, and now when I click on team members' icons in the project Dashboard, nothing happens, no chat box appears at the bottom of the screen like normal. I opened Internet Explorer 8 and logged into the same group and was able to open a chat box for each team member even though they are offline..

I realize this means it is probably a problem with Firefox 4.0 rather than Zoho Projects, but I wanted to report it anyway in case others are thinking of downloading Firefox 4.0.