I can confirm, in 18.04
$ ps v -C mate-panel PID TTY STAT TIME MAJFL TRS DRS RSS %MEM COMMAND 7398 ? Sl 0:29 7 566 1248589 708412 11.6 mate-panel --replace
After ~20 minutes:
PID TTY STAT TIME MAJFL TRS DRS RSS %MEM COMMAND 7398 ? Sl 0:31 7 566 1292469 752760 12.3 mate-panel --replace
I can confirm, in 18.04
$ ps v -C mate-panel
PID TTY STAT TIME MAJFL TRS DRS RSS %MEM COMMAND
7398 ? Sl 0:29 7 566 1248589 708412 11.6 mate-panel --replace
After ~20 minutes:
PID TTY STAT TIME MAJFL TRS DRS RSS %MEM COMMAND
7398 ? Sl 0:31 7 566 1292469 752760 12.3 mate-panel --replace