It's very important you visit this bug and answer if it affects you. There is no real workaround. The bug is random and restarting notification-area-applet until it shows all tray icons is pointless. We're still with the bug and we even don't know what causes it.
I think it's related to Compiz, because switching to Metacity fixes the issue. Note that you have to restart your Qt application after switching to Metacity. So it's possible it's Compiz bug. All possible help needed with this one, if it's Compiz, its team doesn't know how many people are affected by it.
Please, see https:/ /bugs.launchpad .net/ubuntu/ +source/ compiz/ +bug/775196
It's very important you visit this bug and answer if it affects you. There is no real workaround. The bug is random and restarting notification- area-applet until it shows all tray icons is pointless. We're still with the bug and we even don't know what causes it.
I think it's related to Compiz, because switching to Metacity fixes the issue. Note that you have to restart your Qt application after switching to Metacity. So it's possible it's Compiz bug. All possible help needed with this one, if it's Compiz, its team doesn't know how many people are affected by it.