This is really needed feature, asked many peoples. During these processes manager is useless. Also can be start another tuxcmd, but its not comfortable for many copiing/moving.
All the best in the New Year.
Please, implement this in tuxcmd. This is the only feature I really do miss.
The best way to do it, in my opinion, would be to copy total commander's "F2 feature". In TC, you can press F5 and then F2, causing selected file(s) to be added to a queue in the background. This kind of queueing mechanism is indispensable when copying lots of large files.