fix

sprite.cm

@@ -52,8 +52,9 @@ return function(props) {
     rotation: 0,
     color: {r: 1, g: 1, b: 1, a: 1},
     opacity: 1,
+    plane: 'default',
     layer: 0,
-    groups: ['default'],
+    groups: [],
     visible: true
   }
 
@@ -62,7 +63,7 @@ return function(props) {
   for (var k in props) data[k] = props[k]
   
   // Ensure groups is array
-  if (!data.groups) data.groups = ['default']
+  if (!data.groups) data.groups = []
   if (is_text(data.groups)) data.groups = [data.groups]
 
   var s = meme(sprite_proto, data)