diff --git a/dist/extension/js/background.js b/dist/extension/js/background.js
index 129d0f33b5..c0fe71497f 100644
--- a/dist/extension/js/background.js
+++ b/dist/extension/js/background.js
@@ -104,7 +104,7 @@
 
 					let html = '';
 					if (sel.rangeCount) {
-						const container = document.createElement("div");
+						const container = document.createElement('div');
 						for (var i = 0, len = sel.rangeCount; i < len; ++i) {
 							container.appendChild(sel.getRangeAt(i).cloneContents());
 						};
diff --git a/extension/iframe/create.tsx b/extension/iframe/create.tsx
index f4c58169e9..f2c0b724d9 100644
--- a/extension/iframe/create.tsx
+++ b/extension/iframe/create.tsx
@@ -115,11 +115,17 @@ const Create = observer(class Create extends React.Component<I.PageComponent, St
 	initBlocks () {
 		const { html, tabUrl } = extensionStore;
 
-		if (!html || (html == this.html)) {
+		if (html == this.html) {
 			return;
 		};
 
 		this.html = html;
+		blockStore.clear(ROOT_ID);
+
+		if (!html) {
+			this.forceUpdate();
+			return;
+		};
 
 		C.BlockPreview(html, tabUrl, (message: any) => {
 			if (message.error.code) {
diff --git a/extension/iframe/index.tsx b/extension/iframe/index.tsx
index f864ce1216..abbaf405d0 100644
--- a/extension/iframe/index.tsx
+++ b/extension/iframe/index.tsx
@@ -1,6 +1,6 @@
 import * as React from 'react';
 import { observer } from 'mobx-react';
-import { I, UtilRouter, Storage } from 'Lib';
+import { I, Storage } from 'Lib';
 import Util from '../lib/util';
 
 const Index = observer(class Index extends React.Component<I.PageComponent> {