Comment 5 for bug 762722

The problem is that the control panel opens a unity connection to be able to remove the urgency hint. This destroys the existing connection from ubuntuone-client. (That's also the reason we didn't find this before: we only started doing this in the control panel very recently.)

The solution is to have API in ubuntuone-client to remove the urgency hint, and then call that from the control-panel through dbus.