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

Author: omiroshnichenko

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

@@ -213,8 +213,8 @@ define([
 
         /** @inheritdoc */
         destroy: function () {
+            this.pageBuilder && this.pageBuilder.destroy();
             this._super();
-            this.pageBuilder.destroy();
         }
     });
 });

app/code/Magento/PageBuilder/view/adminhtml/web/js/form/element/wysiwyg.js

@@ -50,8 +50,11 @@ export default class Preview extends PreviewCollection {
         super(contentType, config, observableUpdater);
 
         // Keeps track of number of button item to disable sortable if there is only 1.
-        this.contentType.children.subscribe(() => {
+        this.contentType.children.subscribe((args) => {
             const sortableElement = $(this.wrapperElement).find(".buttons-container");
+            if (!sortableElement.data("sortable")) {
+                return;
+            }
             if (this.contentType.children().length <= 1) {
                 sortableElement.sortable("disable");
             } else {