When using the remote desktop application xrdp there is sometimes a problem seeing the windows in Tuner. Changing the window size does not change anything either.
This is due to a combination of the Java gui that Tuner uses and xrdp. To fix the problem the depth setting for xrdp needs to change.
edit /etc/xrdp/xrdp.ini
uncomment line “xserverbpp=24” and save
sudo systemctl restart xrdp.service