I wrote a little XBL component to allow menuitems to have images centered, I added it to Firefox 2 browser context menu and worked fine immediately, after a while I installed component on Firefox 3 beta 4 and surprisingly the menuitem didn’t show the image 😦
I’ve asked help on Mozilla IRC and after about an hour the mistery was revealed.
The innocent CSS declaration shown below works fine on Firefox 2
but requires a little modification on Firefox 3 beta 5pre (at this time the latest available)
You must notice the selector without !important attribute works on Firefox 3 when applied on menus different from browser context menu.
I suspect the browser context menu should have some special treatment on new Firefox…