Comment 23 for bug 1165420

This is clearly a bug and not a design decision (at least, if this is the same issue as #1102493, which I think it is, and which has been marked as a duplicate). Note that the problem is not that you cannot access a non-focused application with the HUD - the problem is that *only* the messaging indicator is inaccessible through the HUD. Since other indicators _are_ accessible, this clearly is not a design decision.

(Note for example that it is also impossible to bring up a chat window though the HUD with someone who started an Empathy conversation with you and thus is listed in the messaging menu.)