Fix destoy method. Closes #3442

src/canvas/index.js

@@ -646,7 +646,7 @@ export default () => {
 
     destroy() {
       canvas.stopListening();
-      CanvasView.remove();
+      CanvasView && CanvasView.remove();
       [c, canvas, CanvasView].forEach(i => (i = {}));
       ['em', 'model', 'droppable'].forEach(i => (this[i] = {}));
     }

src/canvas/view/CanvasView.js

@@ -75,9 +75,9 @@ export default Backbone.View.extend({
   },
 
   remove() {
+    this.frames.remove();
     const frm = this.model.get('frames');
     frm.remove(frm.models);
-    this.frames.remove();
     this.frames = {};
     Backbone.View.prototype.remove.apply(this, arguments);
     this.toggleListeners();