diff --git a/.yarn/patches/react-split-pane-npm-0.1.92-93dbf51dff.patch b/.yarn/patches/react-split-pane-npm-0.1.92-93dbf51dff.patch
deleted file mode 100644
index 7b537aea6..000000000
--- a/.yarn/patches/react-split-pane-npm-0.1.92-93dbf51dff.patch
+++ /dev/null
@@ -1,12 +0,0 @@
-diff --git a/index.d.ts b/index.d.ts
-index d116f54d6da12d24b48e24ff3636c9066059aa58..9d62eac28d5480aa6c2e796d603757d5999ea0af 100644
---- a/index.d.ts
-+++ b/index.d.ts
-@@ -25,6 +25,7 @@ export type SplitPaneProps = {
-   pane2Style?: React.CSSProperties;
-   resizerClassName?: string;
-   step?: number;
-+  children: React.ReactNode;
- };
- 
- export type SplitPaneState = {
diff --git a/packages/ui-default/components/react-splitpane/SplitPaneFillOverlay.page.styl b/packages/ui-default/components/react-splitpane/SplitPaneFillOverlay.page.styl
deleted file mode 100644
index 445e2a10a..000000000
--- a/packages/ui-default/components/react-splitpane/SplitPaneFillOverlay.page.styl
+++ /dev/null
@@ -1,9 +0,0 @@
-.splitpane-fill
-  display: flex
-  position: absolute
-  overflow: hidden
-  left: 0
-  width: 100%
-  top: 0
-  height: 100%
-  user-select: none
diff --git a/packages/ui-default/components/react-splitpane/SplitPaneFillOverlayComponent.jsx b/packages/ui-default/components/react-splitpane/SplitPaneFillOverlayComponent.jsx
deleted file mode 100644
index 0576694dc..000000000
--- a/packages/ui-default/components/react-splitpane/SplitPaneFillOverlayComponent.jsx
+++ /dev/null
@@ -1,19 +0,0 @@
-import classNames from 'classnames';
-import PropTypes from 'prop-types';
-
-export default function SplitPaneFillOverlayComponent(props) {
-  const {
-    className,
-    children,
-    ...rest
-  } = props;
-  const cn = classNames(className, 'splitpane-fill');
-  return (
-    <div {...rest} className={cn}>{children}</div>
-  );
-}
-
-SplitPaneFillOverlayComponent.propTypes = {
-  className: PropTypes.string,
-  children: PropTypes.node,
-};
diff --git a/packages/ui-default/components/react-splitpane/splitpane.page.styl b/packages/ui-default/components/react-splitpane/splitpane.page.styl
deleted file mode 100644
index d66540109..000000000
--- a/packages/ui-default/components/react-splitpane/splitpane.page.styl
+++ /dev/null
@@ -1,27 +0,0 @@
-$resizer-extend = 4px
-$resizer-extend-color = rgba($primary-color, 0.3)
-
-.Resizer
-  background: #000
-  opacity: .2
-  z-index: 1
-  box-sizing: border-box
-  background-clip: padding-box
-
-.Resizer.horizontal
-  height: ($resizer-extend * 2 + 1px)
-  margin: -($resizer-extend) 0
-  border-top: $resizer-extend solid transparent
-  border-bottom: $resizer-extend solid transparent
-  cursor: row-resize
-  width: 100%
-
-.Resizer.vertical
-  width: ($resizer-extend * 2 + 1px)
-  margin: 0 -($resizer-extend)
-  border-left: $resizer-extend solid transparent
-  border-right: $resizer-extend solid transparent
-  cursor: col-resize
-
-.Resizer:hover
-  border-color: $resizer-extend-color
diff --git a/packages/ui-default/components/scratchpad/PanelComponent.jsx b/packages/ui-default/components/scratchpad/PanelComponent.jsx
index 88908fe85..7323942db 100644
--- a/packages/ui-default/components/scratchpad/PanelComponent.jsx
+++ b/packages/ui-default/components/scratchpad/PanelComponent.jsx
@@ -1,7 +1,6 @@
 import classNames from 'classnames';
 import PropTypes from 'prop-types';
 import React from 'react';
-import SplitPaneFillOverlay from 'vj/components/react-splitpane/SplitPaneFillOverlayComponent';
 
 export default function PanelComponent(props) {
   const {
@@ -12,10 +11,10 @@ export default function PanelComponent(props) {
   } = props;
   const cn = classNames(className, 'flex-col');
   return (
-    <SplitPaneFillOverlay {...rest} className={cn}>
+    <div {...rest} className={`${cn} splitpane-fill`}>
       <div className="scratchpad__panel-title">{title}</div>
       <div className="flex-col flex-fill">{children}</div>
-    </SplitPaneFillOverlay>
+    </div>
   );
 }
 
diff --git a/packages/ui-default/components/scratchpad/index.tsx b/packages/ui-default/components/scratchpad/index.tsx
index 842f2b00b..8bc0f44f1 100644
--- a/packages/ui-default/components/scratchpad/index.tsx
+++ b/packages/ui-default/components/scratchpad/index.tsx
@@ -1,39 +1,17 @@
 import ProblemIcon from '@vscode/codicons/src/icons/file.svg?react';
+import { Allotment } from 'allotment';
 import $ from 'jquery';
 import _ from 'lodash';
 import type * as monaco from 'monaco-editor';
 import React from 'react';
 import { useDispatch, useSelector, useStore } from 'react-redux';
-import SplitPane from 'react-split-pane';
 import Dom from 'vj/components/react/DomComponent';
-import SplitPaneFillOverlay from 'vj/components/react-splitpane/SplitPaneFillOverlayComponent';
 import { Context, ctx, Service } from 'vj/context';
 import ScratchpadEditor from './ScratchpadEditorContainer';
 import ScratchpadPretest from './ScratchpadPretestContainer';
 import ScratchpadRecords from './ScratchpadRecordsContainer';
 import ScratchpadToolbar from './ScratchpadToolbarContainer';
 
-function buildNestedPane([a, ...panes], mode: 'horizontal' | 'vertical' = 'horizontal') {
-  const elements = [
-    a,
-    ...panes.filter((p) => p.props.visible),
-  ];
-  if (elements.length === 1) return a;
-  return elements
-    .reduce((prev, curr) => (
-      <SplitPane
-        split={mode}
-        primary="second"
-        defaultSize={curr.props.size}
-        key={curr.element.key}
-        onChange={curr.onChange}
-      >
-        {prev}
-        {curr.element}
-      </SplitPane>
-    ));
-}
-
 const pages = {
   problem: {
     icon: () => <ProblemIcon />,
@@ -88,14 +66,7 @@ export default function ScratchpadContainer() {
   const dispatch = useDispatch();
   const ui = useSelector<any, any>((state) => state.ui, _.isEqual);
 
-  const handleChangeSize = _.debounce((uiElement, size) => {
-    dispatch({
-      type: 'SCRATCHPAD_UI_CHANGE_SIZE',
-      payload: {
-        uiElement,
-        size,
-      },
-    });
+  const handleChangeSize = _.debounce(() => {
     $('#scratchpad').trigger('vjScratchpadRelayout');
     forceUpdate();
   }, 500);
@@ -109,31 +80,20 @@ export default function ScratchpadContainer() {
   const showSidebar = Object.keys(pages).length > 1;
 
   return (
-    <SplitPane
-      split="vertical"
-      primary="first"
-      size={showSidebar ? 50 : 0}
-      allowResize={false}
-    >
-      <div className="scratchpad__tablist" style={{ display: showSidebar ? 'block' : 'none' }}>
-        {Object.keys(pages).map((key) => {
-          const Component = pages[key].icon;
-          return (
-            <div key={key} className={key === ui.activePage ? 'scratchpad__tab-active' : ''} onClick={() => switchToPage(key)}>
-              <Component />
-            </div>
-          );
-        })}
-      </div>
-      <SplitPane
-        defaultSize={ui.main.size}
-        size={ui.main.size}
-        minSize={ui.activePage !== null ? 250 : 0}
-        split="vertical"
-        primary="first"
-        onChange={(size) => handleChangeSize('main', size)}
-        allowResize={ui.activePage !== null}
-      >
+    <Allotment onChange={handleChangeSize}>
+      <Allotment.Pane visible={showSidebar} minSize={50} maxSize={50}>
+        <div className="scratchpad__tablist" style={{ display: showSidebar ? 'block' : 'none' }}>
+          {Object.keys(pages).map((key) => {
+            const Component = pages[key].icon;
+            return (
+              <div key={key} className={key === ui.activePage ? 'scratchpad__tab-active' : ''} onClick={() => switchToPage(key)}>
+                <Component />
+              </div>
+            );
+          })}
+        </div>
+      </Allotment.Pane>
+      <Allotment.Pane visible={!!ui.activePage}>
         <div className="scratchpad__problem">
           {Object.keys(pages).map((key) => {
             const Component = pages[key].component;
@@ -144,23 +104,19 @@ export default function ScratchpadContainer() {
             );
           })}
         </div>
-        {buildNestedPane([
-          <SplitPaneFillOverlay key="editor" className="flex-col">
-            <ScratchpadToolbar />
-            <ScratchpadEditor />
-          </SplitPaneFillOverlay>,
-          {
-            props: ui.pretest,
-            onChange: (size) => handleChangeSize('pretest', size),
-            element: <ScratchpadPretest key="pretest" />,
-          },
-          {
-            props: ui.records,
-            onChange: (size) => handleChangeSize('records', size),
-            element: <ScratchpadRecords key="records" />,
-          },
-        ])}
-      </SplitPane>
-    </SplitPane>
+      </Allotment.Pane>
+      <Allotment vertical onChange={handleChangeSize}>
+        <div key="editor" className="flex-col splitpane-fill">
+          <ScratchpadToolbar />
+          <ScratchpadEditor />
+        </div>
+        <Allotment.Pane visible={ui.pretest.visible}>
+          <ScratchpadPretest key="pretest" />
+        </Allotment.Pane>
+        <Allotment.Pane visible={ui.records.visible}>
+          <ScratchpadRecords key="records" />
+        </Allotment.Pane>
+      </Allotment>
+    </Allotment>
   );
 }
diff --git a/packages/ui-default/context.ts b/packages/ui-default/context.ts
index 14b22cbf1..04a13ba53 100644
--- a/packages/ui-default/context.ts
+++ b/packages/ui-default/context.ts
@@ -8,7 +8,6 @@ export interface Context {
   [Context.events]: Events<Context>;
   setTimeout: typeof setTimeout;
   setInterval: typeof setInterval;
-  setImmediate: typeof setImmediate;
   api: ApiMixin;
 }
 
@@ -37,10 +36,9 @@ const T = <F extends (...args: any[]) => any>(origFunc: F, disposeFunc?) =>
     this.caller?.on('dispose', () => (disposeFunc ? disposeFunc(res) : res()));
   };
 export class ApiMixin extends Service {
-  static readonly methods = ['addScript', 'setInterval', 'setTimeout', 'setImmediate', 'provideModule', 'inject', 'broadcast'];
+  static readonly methods = ['setInterval', 'setTimeout'];
   setInterval = T(setInterval, clearInterval);
   setTimeout = T(setTimeout, clearTimeout);
-  setImmediate = T(setImmediate, clearImmediate);
   constructor(ctx) {
     super(ctx, 'api', true);
   }
diff --git a/packages/ui-default/package.json b/packages/ui-default/package.json
index c851c4da1..a3427b8a1 100644
--- a/packages/ui-default/package.json
+++ b/packages/ui-default/package.json
@@ -40,6 +40,7 @@
     "@types/sharedworker": "^0.0.91",
     "@types/webpack-env": "^1.18.0",
     "@vscode/codicons": "^0.0.32",
+    "allotment": "^1.18.1",
     "autoprefixer": "^10.4.13",
     "browser-update": "^3.3.44",
     "chalk": "^5.2.0",
@@ -87,7 +88,6 @@
     "react-dom": "^18.2.0",
     "react-query": "^3.39.3",
     "react-redux": "^8.0.5",
-    "react-split-pane": "^0.1.92",
     "reconnecting-websocket": "^4.4.0",
     "redux": "^4.2.1",
     "redux-logger": "^3.0.6",
diff --git a/packages/ui-default/theme/default.js b/packages/ui-default/theme/default.js
index 426c2739a..0c7a2a817 100644
--- a/packages/ui-default/theme/default.js
+++ b/packages/ui-default/theme/default.js
@@ -1,5 +1,6 @@
 import 'normalize.css/normalize.css';
 import 'vditor/dist/index.css';
+import 'allotment/dist/style.css';
 import 'pickadate/lib/themes/classic.css';
 import 'pickadate/lib/themes/classic.date.css';
 import 'pickadate/lib/themes/classic.time.css';