Hello, I would love to help with this issue. Do you know how would like to implement it? Maybe with a button like the delete one or directly by selecting from the output panel.

Is there any update on this? I would like to contribute, but don't know where to start.

Nice idea for those able to use touch / gesture rather than scanning, but care will be needed when thinking of placement of symbols to aid correct syntax and may need to think about the impact it has on your crosses for deletion and also ability of the user to move within that small space. Touch sensitivity etc.