I have this same problem with firefox. I've unlocked it from the launcher and the icon disappeared (even though firefox was running) and when I tried to add it again via dragging it from the dash to the launcher it didn't reveal the icon at all, I have an empty spot there now (it doesn't show the tooltip when hovered over), I have attatched a screenshot.
** Attachment added: "Screenshot from 2012-04-07 15:24:56.png" https://bugs.launchpad.net/unity/+bug/772063/+attachment/3022489/+files/Screenshot%20from%202012-04-07%2015%3A24%3A56.png -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/772063 Title: App icon on the Unity Launcher lost track of running instance To manage notifications about this bug go to: https://bugs.launchpad.net/bamf/+bug/772063/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs