This isn't something you can do in noVNC at the moment. It's a good
idea, I've used features like this in other software and I agree it's
often useful.
It's not something someone in the core team has the time to implement
right now however, but we would be open to adding it in the future.
Best regards,
--
Samuel Mannehed Software Development
Cendio AB
https://cendio.com
Teknikringen 8
https://twitter.com/ThinLinc
583 30 Linköping
https://facebook.com/ThinLinc
Phone: +46 13 214 600