diff --git a/.eslintrc.js b/.eslintrc.js
index d66148c..df50b4e 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -7,7 +7,7 @@ module.exports = {
   ],
   parser: '@typescript-eslint/parser',
   parserOptions: {
-    project: 'tsconfig.json',
+    project: 'tsconfig.eslint.json',
     sourceType: 'module'
   },
   plugins: ['@typescript-eslint'],
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 9ccdc80..eb43a81 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -9,26 +9,28 @@ jobs:
     strategy:
       matrix:
         python-version: [3.9, "3.10", "3.11"]
+      fail-fast: false
     steps:
-    - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v4
-      with:
-        python-version: ${{ matrix.python-version }}
     - uses: actions/checkout@v4
-    - name: Install node
-      uses: actions/setup-node@v4
+    - uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
+      # https://github.com/jupyterlab/maintainer-tools/blob/main/.github/actions/base-setup/action.yml
       with:
-       node-version: '18.x'
+        python_version: ${{ matrix.python-version }}
+        node_version: '18.x'
     - name: Install dependencies
-      run: python -m pip install -U jupyterlab~=3.0
-    - name: Build the extension
+      run: python -m pip install -U jupyterlab~=4.0
+    - name: jlpm config
+      run: jlpm config set -H enableImmutableInstalls false
+    - name: install ts modules
+      run: jlpm
+    - name: jlpm lint check
+      run: jlpm run eslint:check
+    - name: install python package
+      run: python -m pip install .
+    - name: check for widgyts in extensions
       run: |
-        jlpm
-        jlpm run eslint:check
-        python -m pip install yt
-        python -m pip install .
-
         jupyter server extension list 2>&1 | grep -ie "widgyts.*OK"
 
         jupyter labextension list 2>&1 | grep -ie "@yt-project/yt-widgets.*OK"
-        python -m jupyterlab.browser_check
+    - name: run jupyterlab browser check
+      run: python -m jupyterlab.browser_check
diff --git a/.gitignore b/.gitignore
index 4c81b4f..787e0bb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -116,5 +116,4 @@ dmypy.json
 
 # yarn build related
 .yarn/
-.yarnrc.yml
 yarn.lock
diff --git a/.yarnrc.yml b/.yarnrc.yml
new file mode 100644
index 0000000..3186f3f
--- /dev/null
+++ b/.yarnrc.yml
@@ -0,0 +1 @@
+nodeLinker: node-modules
diff --git a/README.md b/README.md
index 0275416..c87f4de 100644
--- a/README.md
+++ b/README.md
@@ -41,13 +41,13 @@ The following assumes you're using conda. If not, you'll need to install nodejs
 in your environemnt separately.
 
 ```bash
-conda create -n widgyts-dev -c conda-forge nodejs python=3.10 jupyterlab=3
+conda create -n widgyts-dev -c conda-forge nodejs python=3.10 jupyterlab=4
 conda activate widgyts-dev
 ```
 
 Install the python. This will also build the TS package.
 ```bash
-pip install -e "."
+pip install -e .
 ```
 
 When developing your extensions, you need to manually enable your extensions with the
diff --git a/package.json b/package.json
index 8052b47..b14271b 100644
--- a/package.json
+++ b/package.json
@@ -60,54 +60,45 @@
   },
   "dependencies": {
     "@data-exp-lab/yt-tools": "^0.4.1",
-    "@jupyter-widgets/base": "^1.1.10 || ^2 || ^3 || ^4",
-    "@jupyterlab/application": "^3.0.4",
-    "@jupyterlab/coreutils": "^5.0.2",
-    "@jupyterlab/mainmenu": "^3.0.3",
-    "@jupyterlab/services": "^6.0.3",
+    "@jupyter-widgets/base": "^1.1.10 || ^2 || ^3 || ^4 || ^5 || ^6",
+    "@jupyterlab/application": "^4.2.5",
     "@types/fscreen": "^1.0.1",
     "@types/node": "^10.11.6",
     "@types/three": "^0.141.0",
     "fscreen": "^1.2.0",
-    "ipycanvas": "^0.8.2",
+    "ipycanvas": "^0.13.3",
     "jupyter-threejs": "^2.3.0"
   },
   "devDependencies": {
-    "@jupyterlab/builder": "^3.0.0",
-    "@phosphor/application": "^1.6.0",
-    "@phosphor/widgets": "^1.6.0",
-    "@types/expect.js": "^0.3.29",
-    "@types/mocha": "^5.2.5",
-    "@types/node": "^10.11.6",
-    "@types/webpack-env": "^1.13.6",
-    "@typescript-eslint/eslint-plugin": "^3.6.0",
-    "@typescript-eslint/parser": "^3.6.0",
-    "acorn": "^7.2.0",
-    "css-loader": "^3.2.0",
-    "eslint": "^7.4.0",
-    "eslint-config-prettier": "^6.11.0",
-    "eslint-plugin-prettier": "^3.1.4",
-    "expect.js": "^0.3.1",
-    "fs-extra": "^7.0.0",
-    "karma": "^3.1.0",
-    "karma-chrome-launcher": "^2.2.0",
-    "karma-firefox-launcher": "^1.1.0",
-    "karma-ie-launcher": "^1.0.0",
-    "karma-mocha": "^1.3.0",
-    "karma-mocha-reporter": "^2.2.5",
-    "karma-typescript": "^5.0.3",
-    "karma-typescript-es6-transform": "^5.0.3",
-    "mkdirp": "^0.5.1",
-    "mocha": "^5.2.0",
-    "npm-run-all": "^4.1.3",
-    "prettier": "^2.0.5",
-    "rimraf": "^2.6.2",
-    "source-map-loader": "^0.2.4",
-    "style-loader": "^1.0.0",
-    "ts-loader": "^5.2.1",
-    "typescript": "^4.1.3",
-    "webpack": "^4.20.2",
-    "webpack-cli": "^3.1.2"
+    "@jupyter-widgets/base-manager": "^1.0.7",
+    "@jupyterlab/builder": "^4.0.11",
+    "@lumino/application": "^2.3.0",
+    "@lumino/widgets": "^2.3.1",
+    "@types/webpack-env": "^1.18.4",
+    "@typescript-eslint/eslint-plugin": "^6.19.1",
+    "@typescript-eslint/parser": "^6.19.1",
+    "acorn": "^8.11.3",
+    "css-loader": "^6.9.1",
+    "eslint": "^8.56.0",
+    "eslint-config-prettier": "^9.1.0",
+    "eslint-plugin-prettier": "^5.1.3",
+    "fs-extra": "^11.2.0",
+    "identity-obj-proxy": "^3.0.0",
+    "mkdirp": "^3.0.1",
+    "npm-run-all": "^4.1.5",
+    "prettier": "^3.2.4",
+    "rimraf": "^5.0.5",
+    "source-map-loader": "^5.0.0",
+    "style-loader": "^3.3.4",
+    "ts-loader": "^9.5.1",
+    "typescript": "~5.3.3",
+    "webpack": "^5.90.0",
+    "webpack-cli": "^5.1.4"
+  },
+  "devDependenciesComments": {
+    "@jupyterlab/builder": "pinned to the latest JupyterLab 4.x release",
+    "@lumino/application": "pinned to the latest Lumino 2.x release",
+    "@lumino/widgets": "pinned to the latest Lumino 2.x release"
   },
   "sideEffects": [
     "style/*.css",
diff --git a/pyproject.toml b/pyproject.toml
index da48193..129c652 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,7 +1,8 @@
 [build-system]
 requires = [
-    "hatchling",
-    "jupyterlab~=3.1",
+    "hatchling>=1.21.1",
+    "jupyterlab>=4.0.0,<5",
+    "hatch-nodejs-version>=0.3.2",
 ]
 build-backend = "hatchling.build"
 
@@ -16,7 +17,7 @@ authors = [
 keywords = [
     "Jupyter",
     "JupyterLab",
-    "JupyterLab3",
+    "JupyterLab4",
 ]
 classifiers = [
     "Framework :: Jupyter",
@@ -29,8 +30,8 @@ classifiers = [
 ]
 dependencies = [
     "ipycanvas>=0.4.7",
-    "ipywidgets>=7.5.1",
-    "jupyterlab~=3.0",
+    "ipywidgets>=8.0.0",
+    "jupyterlab>=4.0",
     "numpy>=1.14",
     "pythreejs>=2.2.0",
     "traitlets>=4.3.3",
@@ -49,9 +50,13 @@ Tracker = "https://github.com/yt-project/widgyts/issues"
 
 [tool.hatch.build]
 artifacts = [
+    "widgyts/labextension/*.tgz",
     "widgyts/labextension",
 ]
 
+[tool.hatch.metadata]
+allow-direct-references = true
+
 [tool.hatch.build.targets.wheel.shared-data]
 "widgyts/labextension/static" = "share/jupyter/labextensions/@yt-project/yt-widgets/static"
 "install.json" = "share/jupyter/labextensions/@yt-project/yt-widgets/install.json"
@@ -66,7 +71,7 @@ exclude = [
 
 [tool.hatch.build.hooks.jupyter-builder]
 dependencies = [
-    "hatch-jupyter-builder>=0.9.1",
+    "hatch-jupyter-builder>=0.8.3",
 ]
 build-function = "hatch_jupyter_builder.npm_builder"
 ensured-targets = [
@@ -77,7 +82,15 @@ skip-if-exists = [
     "widgyts/labextension/static/style.js",
 ]
 
+[tool.hatch.build.hooks.jupyter-builder.build-kwargs]
+path = "."
+build_cmd = "build:prod"
+npm = [
+    "jlpm",
+]
+
 [tool.hatch.build.hooks.jupyter-builder.editable-build-kwargs]
+path = "."
 build_dir = "widgyts/labextension"
 source_dir = "src"
 build_cmd = "install:extension"
@@ -85,11 +98,7 @@ npm = [
     "jlpm",
 ]
 
-[tool.hatch.build.hooks.jupyter-builder.build-kwargs]
-build_cmd = "build:prod"
-npm = [
-    "jlpm",
-]
+
 
 [tool.black]
 line-length = 88
diff --git a/src/fullscreen.ts b/src/fullscreen.ts
index 2ef7b43..2a2ea9a 100644
--- a/src/fullscreen.ts
+++ b/src/fullscreen.ts
@@ -50,7 +50,7 @@ export class FullscreenButtonView extends DOMWidgetView {
     this.el.classList.add('jupyter-widgets');
     this.el.classList.add('jupyter-button');
     this.el.classList.add('widget-button');
-    this.delegate('click', this.el, this._handle_click);
+    this.delegate('click', this.el.value, this._handle_click);
     this.update(); // Set defaults.
   }
 
diff --git a/tsconfig.eslint.json b/tsconfig.eslint.json
new file mode 100644
index 0000000..0a76836
--- /dev/null
+++ b/tsconfig.eslint.json
@@ -0,0 +1,5 @@
+{
+  "extends": "./tsconfig.json",
+  "include": ["src/**/*.ts", "src/**/*.tsx"],
+  "exclude": []
+}