contextmenu was renamed to onContextMenu, this fixes the event listener

examples/js/controls/OrbitControls.js

@@ -218,7 +218,7 @@ THREE.OrbitControls = function ( object, domElement ) {
 
 	this.dispose = function() {
 
-		scope.domElement.removeEventListener( 'contextmenu', contextmenu, false );
+		scope.domElement.removeEventListener( 'contextmenu', onContextMenu, false );
 		scope.domElement.removeEventListener( 'mousedown', onMouseDown, false );
 		scope.domElement.removeEventListener( 'mousewheel', onMouseWheel, false );
 		scope.domElement.removeEventListener( 'MozMousePixelScroll', onMouseWheel, false ); // firefox