Updated: works on FF22-24+!! Does not work with "Flashblock" installed. Rated 5 out of 5 stars
Thankfully, we don't need Flashblock any more: with Firefox 24, you can pick "ask to activate", en then, where there is Flash on a page, click it and pick "always allow Flash on this website", at last!
addon works fine
I just updated firefox to 23.0. This addon still works fine.
Which operating system you are using?
Did you try to press Ctrl+T when focus is in flash? (It works.)
Which site you are trying?