--- a/browser/components/extensions/ext-sidebarAction.js
+++ b/browser/components/extensions/ext-sidebarAction.js
@@ -136,26 +136,16 @@ this.sidebarAction = class extends Exten
     let install = this.extension.startupReason === "ADDON_INSTALL";
     for (let window of windowTracker.browserWindows()) {
       this.updateWindow(window);
       let {SidebarUI} = window;
       if (install || SidebarUI.lastOpenedId == this.id) {
         SidebarUI.show(this.id);
       }
     }
-
-    if (install && !Services.prefs.prefHasUserValue("extensions.sidebar-button.shown")) {
-      Services.prefs.setBoolPref("extensions.sidebar-button.shown", true);
-      // If the sidebar button has never been moved to the toolbar, move it now
-      // so the user can see/access the sidebars.
-      let widget = CustomizableUI.getWidget("sidebar-button");
-      if (!widget.areaType) {
-        CustomizableUI.addWidgetToArea("sidebar-button", CustomizableUI.AREA_NAVBAR, 0);
-      }
-    }
   }
 
   sidebarUrl(panel) {
     let url = `${sidebarURL}?panel=${encodeURIComponent(panel)}`;
 
     if (this.extension.remote) {
       url += "&remote=1";
     }

--- a/browser/components/extensions/test/browser/browser_ext_sidebarAction.js
+++ b/browser/components/extensions/test/browser/browser_ext_sidebarAction.js
@@ -46,37 +46,29 @@ let extData = {
 
 add_task(async function sidebar_initial_install() {
   ok(document.getElementById("sidebar-box").hidden, "sidebar box is not visible");
   let extension = ExtensionTestUtils.loadExtension(extData);
   await extension.startup();
   // Test sidebar is opened on install
   await extension.awaitMessage("sidebar");
   ok(!document.getElementById("sidebar-box").hidden, "sidebar box is visible");
-  // Test toolbar button is available
-  ok(document.getElementById("sidebar-button"), "sidebar button is in UI");
 
   await extension.unload();
   // Test that the sidebar was closed on unload.
   ok(document.getElementById("sidebar-box").hidden, "sidebar box is not visible");
-
-  // Move toolbar button back to customization.
-  CustomizableUI.removeWidgetFromArea("sidebar-button", CustomizableUI.AREA_NAVBAR);
-  ok(!document.getElementById("sidebar-button"), "sidebar button is not in UI");
 });
 
 
 add_task(async function sidebar_two_sidebar_addons() {
   let extension2 = ExtensionTestUtils.loadExtension(extData);
   await extension2.startup();
   // Test sidebar is opened on install
   await extension2.awaitMessage("sidebar");
   ok(!document.getElementById("sidebar-box").hidden, "sidebar box is visible");
-  // Test toolbar button is NOT available after first install
-  ok(!document.getElementById("sidebar-button"), "sidebar button is not in UI");
 
   // Test second sidebar install opens new sidebar
   let extension3 = ExtensionTestUtils.loadExtension(extData);
   await extension3.startup();
   // Test sidebar is opened on install
   await extension3.awaitMessage("sidebar");
   ok(!document.getElementById("sidebar-box").hidden, "sidebar box is visible");
   await extension3.unload();
@@ -92,13 +84,8 @@ add_task(async function sidebar_empty_pa
   await extension.startup();
   // Test sidebar is opened on install
   await extension.awaitMessage("sidebar");
   ok(!document.getElementById("sidebar-box").hidden, "sidebar box is visible in first window");
   extension.sendMessage("set-panel");
   await extension.awaitFinish();
   await extension.unload();
 });
-
-add_task(async function cleanup() {
-  // This is set on initial sidebar install.
-  Services.prefs.clearUserPref("extensions.sidebar-button.shown");
-});