Hello, Sometimes ( we can't trace the trigger) we're experiencing wird behavior of the Thunderbird All of the sudden cursor in editor (text input areas) starts to run back, as one would hold left/back/ arrow. First thought was it is a virus, but apparently there is none. at that time In left folder menu: when selected folder tree starts to collapse to root (sub-folders can not be accessible) in drop-down menu: when selected, it starts to move to another drop-down continuously

if we restart application, problem is still there, only if we restart the computer, we can use thunderbird again until next time problems appears. system: Win 7 home edition