Beta1 works good! Rated 5 out of 5 stars

Beta1 works whithout any problem!
Many thanks and success in everything!

This review is for a previous version of the add-on (0.9.3.1-signed). 

Good idea but It does not work :( Rated 5 out of 5 stars

"try the beta version of 0.9.4 offered below and let me know if it works."
It does not work :(
But your idea is very good. Very wait next working version.

This review is for a previous version of the add-on (0.9.3.1-signed). 

Thanks for your review!
I assume you installed the beta 2? Could you try the beta 1: https://addons.mozilla.org/de/firefox/addon/flashdisable/versions/0.9.4beta1
Version 2 does not contain the "aggressive" fix. It could be that this version makes a button of another addon disappear though.

The problem is, that there is no standard api yet to display buttons and every addon has to fiddle around. Fortunately the new firefox design "Australis" which will probably be published with Firefox 29 will include a api that will make the button work once and for all. :-)

Edit: The button should always be in the customize toolbar panel, even in versions without the aggressive fix.