insert-box in editor<%>

Inserts a box (a sub-editor) into the editor.

The content of an editor can be changed by the system in response to other method calls, and such changes do not go through this method; use on-insert in text% or on-insert in pasteboard% to monitor content additions changes.

• (send an-editor insert-box type) -> void
     type = 'text : symbol in '(text pasteboard)

  Calls on-new-box, passing along type and inserts the resulting snip into the editor.