code: function( skipContentCompare ) {
  			var undoManager = this.undoManager;
  
  			// We attempt to save content snapshot, if content didn't change, we'll
  			// only amend selection.
  			if ( skipContentCompare || !undoManager.save( true, null, false ) )
  				undoManager.updateSelection( new Image( undoManager.editor ) );
  
  			undoManager.resetType();
  		}
docs: Method called for navigation change. At first it will check if current content does not differ
  from the last saved snapshot.
  
  * If the content is different, the method creates a standard, extra snapshot.
  * If the content is not different, the method will compare the selection, and will
  amend the last snapshot selection if it changed.
  
  @param {Boolean} skipContentCompare If set to `true`, it will not compare content, and only do a selection check.