SSH-Tunneled VNC connection randomly hangs

Created by: dktrkranz

[ forwarded from https://bugs.debian.org/698890 ]

While connecting to a remote desktop through a tunneled VNC session, the session will at some point stop responding to input and/or refuse to disconnect or close. Attempting to disconnect results in both the child VNC window hanging and the parent Remmina session window hanging as well. Attempting to close the window via the window manager exhibits the same behavior.

To reproduce: Create a VNC connection that tunnels via SSH Connect to a remote desktop that has a 24 or 32 bit color depth Use the session for a few minutes, then let it idle. While it does not matter if the VNC window is minimized or not, generally you can leave it displayed. Wait for a period of time, say 5 minutes Attempt to disconnect, or close the window. At this point, both the child and parent windows will "hang" and stop responding to input. Your only effective option is to kill the parent task.

Expected results: The window should continue to respond to input, barring interruptions in the IP connection to the remote session. If this is a function of the SSH tunnel losing the connection, it should auto- connect, or use some form of keep-alive while the window is displayed.