I expect the "envelope" from the messaging menu to turn blue only where there is a pending notification (like a new mail or a new IM message). When I click it, I usually see from which app the notification come from.
Sometime, the envelope turn blue, but there is no notification. When I click the envelope, I don't see any app with notifications pending. I can "clean" the notifications to change the color to white, but the envelope will turn blue again after some minutes.
The only solution I found is to reboot the computer...
Is it a known bug? There is a way to get the application that send this notification? I didn't find anything about that after a Google search.
I still didn't find way to get a "debug view" of the messaging menu. I found dbus-monitor but this just spam too much and I can't find anything useful from that.
Seem like I'm missing some messages from Pidgin (xmpp). I'm thinking that the messaging icon become blue to warn me a new message was received, but Pidgin fails to show me that message.