docs: function mxDefaultKeyHandler(editor)
  {
  	if (editor != null)
  	{
  		this.editor = editor;
  		this.handler = new mxKeyHandler(editor.graph);
  		
  		// Extends the escape function of the internal key
  		// handle to hide the properties dialog and fire
  		// the escape event via the editor instance
  		var old = this.handler.escape;
  		
  		this.handler.escape = function(evt)
  		{
  			old.apply(this, arguments);
  			editor.hideProperties();
  			editor.fireEvent(new mxEventObject(mxEvent.ESCAPE, 'event', evt));
  		};
  	}
  }