Editor: Ignore Sprites when updating selectionBox.

editor/js/Viewport.js

@@ -272,7 +272,8 @@ var Viewport = function ( editor ) {
 
 		if ( object !== null ) {
 
-			if ( object.geometry !== undefined ) {
+			if ( object.geometry !== undefined &&
+				 object instanceof THREE.Sprite === false ) {
 
 				selectionBox.update( object );
 				selectionBox.visible = true;