Comment 5 for bug 1235754

metRo_, not in Ubuntu/Unity. A nasty workaround for Xubuntu is to remove the indicator-application package. That will at least allow the tray icon to appear, but if anything else uses that package, you will lose that as well. For example, the volume indicator.

The Quassel team states that this is a won't-fix because Canonical changed the way this works in incompatible ways. I don't agree with this, but it is what it is. If anyone wants to step up and write a patch, that would be awesome. However, for now, I just accept the fact that there is no indicator or tray icon in Unity for Quassel.