button doesnt turn purple immediately for private browsing Rated 3 out of 5 stars

the button isnt purple when in private browsing mode, it only turns purple when you mouse over it, is this a bug?

This review is for a previous version of the add-on (1.1). 

Version 1.2 of the bug has been fixed
https://addons.mozilla.org/firefox/downloads/file/128288/new_firefox_button_menu-1.2-fx.xpi