Use isCountable in ItemView render

src/navigator/view/ItemView.js

@@ -343,9 +343,9 @@ export default Backbone.View.extend({
   },
 
   render() {
-    const { model, config, pfx, ppfx } = this;
-    const hidden =
-      (config.hideTextnode && model.is('textnode')) || !model.get('layerable');
+    const { model, config, pfx, ppfx, opt } = this;
+    const { isCountable } = opt;
+    const hidden = isCountable && !isCountable(model, config.hideTextnode);
     const vis = this.isVisible();
     const el = this.$el.empty();
     const level = this.level + 1;