perf + fix for attributes and custom VNode

Author: Gorash

packages/plugin-layout/src/ZoneNode.ts

@@ -43,6 +43,8 @@ export class ZoneNode extends ContainerNode {
     _removeAtIndex(index: number): void {
         const child = this.childVNodes[index];
         super._removeAtIndex(index);
-        delete this.hidden[child.id];
+        if (this.hidden) {
+            delete this.hidden[child.id];
+        }
     }
 }

packages/plugin-theme/src/ThemeXmlDomParser.ts

@@ -20,7 +20,7 @@ export class ThemeXmlDomParser extends AbstractParser<Node> {
     async parse(item: Element): Promise<VNode[]> {
         const theme = new ThemeNode({ theme: item.getAttribute('name') });
         const attributes = this.engine.parseAttributes(item);
-        attributes.classList.remove('name');
+        attributes.remove('name');
         if (attributes.length) {
             theme.modifiers.append(attributes);
         }

packages/plugin-xml/src/Attributes.ts

@@ -54,8 +54,12 @@ export class Attributes extends Modifier {
         if (this._record) {
             clone._record = makeVersionable({ ...this._record });
         }
-        clone.style = this.style.clone();
-        clone.classList = this.classList.clone();
+        if (this.style.length) {
+            clone.style = this.style.clone();
+        }
+        if (this.classList.length) {
+            clone.classList = this.classList.clone();
+        }
         return clone;
     }
     /**