PB-166: Page Builder doesn't implement destroy method

Author: omiroshnichenko

app/code/Magento/PageBuilder/view/adminhtml/web/js/content-type-collection.js

@@ -142,6 +142,14 @@ export default class Preview extends PreviewCollection {
         }, 1));
     }
 
+    /**
+     * Remove focused tab
+     */
+    public destroy(): void {
+        super.destroy();
+        _.defer(() => this.setFocusedTab(null));
+    }
+
     /**
      * Refresh the tabs instance when new content appears
      *