lectionCells(), dx, dy);
					}
			    };

				// Transfer initial focus to graph container for keystroke handling
				graph.container.focus();
				    
			    // Handles keystroke events
			    var keyHandler = new mxKeyHandler(graph);
			    
			    // Ignores enter keystroke. Remove this line if you want the
			    // enter keystroke to stop editing
			    keyHandler.enter = function() {};
			    
			    keyHandler.bindKey(37, function()
				{
					nudge(37);
				});
			    
			    keyHandler.bindKey(38,