Open multiple selected files in registered or external editor

[ryandenki]

Currently when selecting multiple files and right-clicking to bring up the context menu, the "Open ..." options are greyed out.

This means you cannot open a selected set of files in the editor together, but must deselect all files, then individually one-by-one open the context menu and select the appropriate "Open ..." option each time.

It would be helpful to be able to open multiple files in an editor, perhaps by iterating over the list and opening each one separately.