Comment 47 for bug 484610

The branch at lp:~psybers/docky/bug518828 has the ability to fix this bug as well. You have to manually add a StartupWMClass=<foo> attribute to your launchers, but once you do it should match. The value of that attribute should be the WM_CLASS of the window.

To get the value, run "xprop | grep WM_CLASS" and click on the window. It should dump something like this:

WM_CLASS(STRING) = "Navigator", "Firefox"

You then copy/paste the 2nd quoted string. So for this example I would add:

StartupWMClass=Firefox

to the launcher firefox.desktop and it should match based on the class (note that firefox actually already has this attribute in their launcher).