i donÃ‚Â´t know, if this bug hast been posted or not. So i will post it ;)
First my system: Mac OS, firefox 22.214.171.124
If i jumt with my tab-button on my keyboard into the Content Area of the TinyMCE, the editor is not actice (i am not able to klick any button). But if if klick into the content area of the TinyMCE, the editor is actice, so i can click all button.
I hope i could help to improove this verry gread cms!!!!