Guessing but.... Are you using Internet Explorer?
Hi I have the same problem.
I have moodle 2.6 and the tool bar of Tinymce not appear. I tested on mozzila, explorer and googlecrome.
But when I delete all the cookies, history, and cache the bar appear just one time, and if you want to edit other block the bar will not appera never more.
I´ll appreciate you help, so I have a big problem with this.
Thanks.