diff --git a/packages/application/style/base.css b/packages/application/style/base.css
index 35378129f5..92d203720e 100644
--- a/packages/application/style/base.css
+++ b/packages/application/style/base.css
@@ -59,7 +59,6 @@ body {
 }
 
 #main-panel {
-  box-shadow: var(--jp-elevation-z4);
   margin-left: auto;
   margin-right: auto;
   max-width: var(--jp-notebook-max-width);
@@ -71,6 +70,10 @@ body {
 
 /* Special case notebooks as document oriented pages */
 
+[data-notebook]:not(body[data-notebook='notebooks']) #main-panel {
+  box-shadow: var(--jp-elevation-z4);
+}
+
 body[data-notebook='notebooks'] #main-panel {
   margin-left: unset;
   margin-right: unset;
diff --git a/packages/tree-extension/src/index.ts b/packages/tree-extension/src/index.ts
index 8b48230c7b..92745166f1 100644
--- a/packages/tree-extension/src/index.ts
+++ b/packages/tree-extension/src/index.ts
@@ -159,6 +159,7 @@ const notebookTreeWidget: JupyterFrontEndPlugin<INotebookTree> = {
 
     nbTreeWidget.addWidget(browser);
     nbTreeWidget.tabBar.addTab(browser.title);
+    nbTreeWidget.tabsMovable = false;
 
     // Toolbar
     toolbarRegistry.addFactory(
diff --git a/packages/tree-extension/style/base.css b/packages/tree-extension/style/base.css
new file mode 100644
index 0000000000..1eb5667ab3
--- /dev/null
+++ b/packages/tree-extension/style/base.css
@@ -0,0 +1,17 @@
+/*-----------------------------------------------------------------------------
+| Copyright (c) Jupyter Development Team.
+|
+| Distributed under the terms of the Modified BSD License.
+|----------------------------------------------------------------------------*/
+
+.jp-FileBrowser-toolbar .jp-Toolbar-item.jp-DropdownMenu,
+.jp-FileBrowser-toolbar .jp-Toolbar-item.jp-ToolbarButton,
+.jp-FileBrowser-toolbar .jp-Toolbar-item.jp-CommandToolbarButton {
+  border: solid 1px var(--jp-border-color2);
+  margin: 1px;
+  padding: 0px;
+}
+
+.jp-FileBrowser-toolbar button.jp-ToolbarButtonComponent {
+  height: 100%;
+}
diff --git a/packages/tree-extension/style/index.css b/packages/tree-extension/style/index.css
index 078667ad6e..f989a1da69 100644
--- a/packages/tree-extension/style/index.css
+++ b/packages/tree-extension/style/index.css
@@ -1,3 +1,11 @@
+/*-----------------------------------------------------------------------------
+| Copyright (c) Jupyter Development Team.
+|
+| Distributed under the terms of the Modified BSD License.
+|----------------------------------------------------------------------------*/
+
 @import url('~@jupyterlab/filebrowser/style/index.css');
 
 @import url('~@jupyter-notebook/tree/style/index.css');
+
+@import './base.css';
diff --git a/packages/tree-extension/style/index.js b/packages/tree-extension/style/index.js
index 406d1565af..6983d18337 100644
--- a/packages/tree-extension/style/index.js
+++ b/packages/tree-extension/style/index.js
@@ -1,3 +1,5 @@
 import '@jupyterlab/filebrowser/style/index.js';
 
 import '@jupyter-notebook/tree/style/index.js';
+
+import './base.css';
diff --git a/packages/tree/style/base.css b/packages/tree/style/base.css
index 0f86d8b839..a5a9ccb943 100644
--- a/packages/tree/style/base.css
+++ b/packages/tree/style/base.css
@@ -18,6 +18,7 @@
 }
 
 .jp-TreePanel .lm-TabBar-tab {
+  flex: 0 1 auto;
   color: var(--jp-ui-font-color0);
   font-size: var(--jp-ui-font-size1);
   height: 100%;
diff --git a/ui-tests/test/mobile.spec.ts-snapshots/tree-chromium-linux.png b/ui-tests/test/mobile.spec.ts-snapshots/tree-chromium-linux.png
index 4da6e6a6ab..662378715c 100644
Binary files a/ui-tests/test/mobile.spec.ts-snapshots/tree-chromium-linux.png and b/ui-tests/test/mobile.spec.ts-snapshots/tree-chromium-linux.png differ
diff --git a/ui-tests/test/mobile.spec.ts-snapshots/tree-firefox-linux.png b/ui-tests/test/mobile.spec.ts-snapshots/tree-firefox-linux.png
index b941b759d4..53a325c2ea 100644
Binary files a/ui-tests/test/mobile.spec.ts-snapshots/tree-firefox-linux.png and b/ui-tests/test/mobile.spec.ts-snapshots/tree-firefox-linux.png differ
diff --git a/ui-tests/test/settings.spec.ts-snapshots/top-hidden-chromium-linux.png b/ui-tests/test/settings.spec.ts-snapshots/top-hidden-chromium-linux.png
index 98b2874a67..641b895671 100644
Binary files a/ui-tests/test/settings.spec.ts-snapshots/top-hidden-chromium-linux.png and b/ui-tests/test/settings.spec.ts-snapshots/top-hidden-chromium-linux.png differ
diff --git a/ui-tests/test/settings.spec.ts-snapshots/top-hidden-firefox-linux.png b/ui-tests/test/settings.spec.ts-snapshots/top-hidden-firefox-linux.png
index 2a1c92341b..baed517d91 100644
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diff --git a/ui-tests/test/settings.spec.ts-snapshots/top-visible-chromium-linux.png b/ui-tests/test/settings.spec.ts-snapshots/top-visible-chromium-linux.png
index 82798761c4..dbcabaf391 100644
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diff --git a/ui-tests/test/settings.spec.ts-snapshots/top-visible-firefox-linux.png b/ui-tests/test/settings.spec.ts-snapshots/top-visible-firefox-linux.png
index 7fbdd97907..4935d8434e 100644
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