Implement the ability to hide kmail in the message indicator widget only
Binary package hint: kdepim
When Kopete's systray icon is disabled in the configuration, it is possible to hide the contact list using the "close" button (in the top right corner), without really closing the application. That's a really nice option imo, because in Kubuntu default desktop Kopete is already displayed in the message indicator widget in the systray.
It should be nice if the same behaviour could be achieved with Kmail (I didn't check Quassel & Konvi as I'm not using them) and AFAIK this is not possible right now. When the systray icon is disabled, hitting the "close" button terminates the program. Enabling the systray icon is not really useful (I use the message indicator widget instead), and I even noticed some annoying paiting issues trying to expand the systray when kmail's icon is hidden.
I guess this would be a nice improvement for Kubuntu user interface (even if it's optional).