This affects only the latest ISO image 21.02-rc1-Foltest-210117.
Small typo in openbox configuration file rc.xml which block keyboard shortcut Alt-PrintScr.
To fix just run command:
sed -i.bak 's/A=Print/A-Print/' $HOME/.config/openbox/rc.xml
Then reload openbox by super-r
Now Alt-PrintScr should work as intended.
