Implemented by subclasses to delete the selection, if there is one, or a single character backward from the insertion point.
Original signature is '- (void)deleteBackwardByDecomposingPreviousCharacter:(id)sender'
Available in Mac OS X v10.3 and later.


- sender (Id)
- Typically the object that invoked this method.

- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)