code: protected void doUndo(int oldCursorPos, String oldText) {
  		if (oldText != null) {
  			setText(oldText);
  			setCursorPos(oldCursorPos);
  		}
  	}
docs: Do the undo of the paste, overrideable for custom behaviour
  
  @param oldCursorPos before the paste
  @param oldText The text before the last paste