The ability to have an additional right-click command to be able to open a file readonly into the configured editor.
I often have many dozens of files open in my editor at any one time but most of them are only for tracing through code so do not need to be, indeed should not be, editable. There is also considerable overhead on SCP monitoring all these open files.
Therefore I want to be able to transfer the file into my editor and then forget about it.
the editor itself does not necessarily need to know that it is readonly, just have scp forget about it (although it would be a nice feature for scp to give a warning if the user subsequently tries to save it).