Reminna has unusable framerate when clipboard sync turned on

[Jon Brase]

On an intermittent basis, Remmina will, if clipboard sync is on, drop to an unusably low framerate after login to the remote machine. I have not managed to fully determine the conditions under which this occurs: it appears to happen or not happen consistently across a login session on the local machine (conditional upon clipboard sync being on), or possibly across a boot of the local machine. I have noticed it start occurring or stop occurring on reboots. When it occurs, it occurs for both remote machines I have set up (A Raspberry Pi 2 running Ubuntu Mate 18.04 and an x86 server running Debian Bullseye with LxQT). When it does not occur, it does not occur for either machine (this seems to include the case where clipboard sync has been turned off for one remote machine and not the other and the connections are open simultaneously, in which case the issue appears on neither!).

The local machine is running Kubuntu 20.04, though some Mate components are also running on top of KDE. The connection is made via RDP, to xrdp v 0.6.x on the Raspberry Pi and xrdp 0.9.12 on the x86 server. All devices are in the same room, with gigabit ethernet connections. I have verified that I am getting gigabit bandwidth with iperf3, and ping latencies are sub-millisecond.

Remmina is version 1.4.2+dfsg-1ubuntu1