The StartupWMClass key in the firefox.desktop file is incorrect in Fedora 17. It currently is set to "Firefox-bin", but the correct value is "Firefox". This will prevent the Firefox icon from showing up twice in Docky and the Unity launcher. By the way, the correct value was found by running "xprop | grep WM_CLASS" and clicking a Firefox window.
WM_CLASS(STRING) = "Navigator", "Firefox" says my Firefox. AFAIK StartupWMClass is unused. Does Unity accept it?
That's what mine says too. Here's what happens when StartupWMClass is set to the current "Firefox-bin": http://i.imgur.com/z3aFw.jpg And when StartupWMClass is set to "Firefox": http://i.imgur.com/4t2n3.jpg If you look at the launcher in the first picture, the Firefox icon shows up twice. If StartupWMClass is removed, everything works as expected :)
Okay. The StartupWMClass is unused in gnome anyway.
Added to rawhide.