I do not know what should happen, but I run Mumble on window manager which doesn't have any system tray.
I decided to 'minimize' Mumble. (It is asking about it as default when closing when connected)
I got error:
X Error: BadMatch (invalid parameter attributes) 8
Major opcode: 42 (X_SetInputFocus)
Resource id: 0x3800015
But I got what I asked: Mumble was running without window and there weren't any way to make it visible again.
Is there way that Mumble can ask (from system) is minimizing possible at all? Or is this totally stupidness of user?
self-compiled Mumble-1.2.2, on matchbox ( http://matchbox-project.org/ )