After upgrading WordPress to version 3.5 at first the tinymce plugin would not load. On the post window you had 2 tabs Text / Visual it was stuck on text you couldn't swap to visual and no buttons loaded.
once I went into settings and reconfirmed all the options and clicked save
it worked but is VERY VERY slow to load now and the icons don't seem to fit anymore there are spaces and some buttons like mailto, imagemap dont seem to work for me.
don't know if it's strictly the new wordpress 3.5 or another plugin I wanted to post this just in case, as it's late I'm gonna test tomorrow morning going through and disabling plugins or reinstalling plugins and see what happens