I've been reading reports that the method of injecting buttons into the mce editor has changed in wp 3.3 which may be the root of the problem I'm having which is this:
After activating the plugin, creating a shortcode, the button I've created works as expected on the HTML tab, but the rich editor's buttons disappear when on the add a new post screen. I've verified this on Firefox, Chrome and Safari on Mac OS X and Firefox on Windows. Interestingly, IE7 on XP, after an extended time, does eventually show the buttons. Possibly relatedly, a plugin that does something very similar to this one (http://wordpress.org/extend/plugins/addquicktag/) causes exactly the same problem.
Any information you can provide would be very helpful.