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-delete to monitor content deletion changes.
Deletes the specified range in the editor. If start is 'start, then the starting selection position is used; if end is 'back, then only the character preceding start is deleted. If scroll-ok? is not #f and start is the same as the current caret position, then the editor's display may be scrolled to show the new selection position.
Deletes the currently selected text.