diff --git a/browser/components/customizableui/CustomizableUI.jsm b/browser/components/customizableui/CustomizableUI.jsm
index 1e5142f95099..3deede917e03 100644
--- a/browser/components/customizableui/CustomizableUI.jsm
+++ b/browser/components/customizableui/CustomizableUI.jsm
@@ -2083,14 +2083,16 @@ var CustomizableUIInternal = {
       this.showWidgetView(aWidget, aNode, aEvent);
     } else if (aWidget.type == "button-and-view") {
       // Do the command if we're in the toolbar and the button was clicked.
-      // Otherwise, open the view. There is no way to trigger the command while
+      // Otherwise, including when we have currently overflowed out of the
+      // toolbar, open the view. There is no way to trigger the command while
       // the widget is in the panel, by design.
       let button = aNode.firstElementChild;
       let area = this.getPlacementOfWidget(aNode.id).area;
       let areaType = CustomizableUI.getAreaType(area);
       if (
         areaType == CustomizableUI.TYPE_TOOLBAR &&
-        button.contains(aEvent.target)
+        button.contains(aEvent.target) &&
+        !aNode.hasAttribute("overflowedItem")
       ) {
         this.doWidgetCommand(aWidget, aNode, aEvent);
       } else {
diff --git a/browser/components/downloads/test/browser/browser_overflow_anchor.js b/browser/components/downloads/test/browser/browser_overflow_anchor.js
index e92046775a02..e02ed8115743 100644
--- a/browser/components/downloads/test/browser/browser_overflow_anchor.js
+++ b/browser/components/downloads/test/browser/browser_overflow_anchor.js
@@ -1,9 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
-// This is the same value used by CustomizableUI tests.
-const kForceOverflowWidthPx = 450;
-
 registerCleanupFunction(async function() {
   // Clean up when the test finishes.
   await task_resetState();
diff --git a/browser/themes/shared/customizableui/panelUI.inc.css b/browser/themes/shared/customizableui/panelUI.inc.css
index bd844fa50edc..7a415fc57719 100644
--- a/browser/themes/shared/customizableui/panelUI.inc.css
+++ b/browser/themes/shared/customizableui/panelUI.inc.css
@@ -1778,7 +1778,8 @@ toolbarpaletteitem[place="menu-panel"] > toolbaritem {
   -moz-box-flex: 1;
 }
 
-.toolbaritem-combined-buttons[cui-areatype="menu-panel"] > .toolbarbutton-combined-buttons-dropmarker {
+.toolbaritem-combined-buttons[cui-areatype="menu-panel"] > .toolbarbutton-combined-buttons-dropmarker,
+.toolbaritem-combined-buttons[overflowedItem] > .toolbarbutton-combined-buttons-dropmarker {
   display: none;
 }
 
diff --git a/devtools/client/performance-new/test/browser/browser_split-toolbar-button.js b/devtools/client/performance-new/test/browser/browser_split-toolbar-button.js
index a4efd5c74e82..fe100a7110ce 100644
--- a/devtools/client/performance-new/test/browser/browser_split-toolbar-button.js
+++ b/devtools/client/performance-new/test/browser/browser_split-toolbar-button.js
@@ -4,6 +4,9 @@
 
 "use strict";
 
+// This is the same value used by CustomizableUI tests.
+const kForceOverflowWidthPx = 450;
+
 function isActive() {
   return Services.profiler.IsActive();
 }
@@ -83,6 +86,53 @@ add_task(async function click_dropmarker() {
   ok(!dropmarker.hasAttribute("open"), "panel should be closed");
 });
 
+add_task(async function click_overflowed_icon() {
+  info("Test that the profiler icon opens the panel when overflowed.");
+
+  const overflowMenu = document.getElementById("widget-overflow");
+  const profilerPanel = document.getElementById("PanelUI-profiler");
+
+  ok(!dropmarker.hasAttribute("open"), "should start with the panel closed");
+  ok(!isActive(), "should start with the profiler inactive");
+
+  const navbar = document.getElementById(CustomizableUI.AREA_NAVBAR);
+  ok(
+    !navbar.hasAttribute("overflowing"),
+    "Should start with a non-overflowing toolbar."
+  );
+
+  info("Force the toolbar to overflow.");
+  const originalWindowWidth = window.outerWidth;
+  window.resizeTo(kForceOverflowWidthPx, window.outerHeight);
+  await TestUtils.waitForCondition(() => navbar.hasAttribute("overflowing"));
+  ok(navbar.hasAttribute("overflowing"), "Should have an overflowing toolbar.");
+
+  info("Open the overflow menu.");
+  const chevron = document.getElementById("nav-bar-overflow-button");
+  chevron.click();
+  await TestUtils.waitForCondition(() => overflowMenu.state == "open");
+
+  info("Open the profiler panel.");
+  button.click();
+  await TestUtils.waitForCondition(() =>
+    profilerPanel?.hasAttribute("visible")
+  );
+
+  info("Ensure the panel is open and the profiler still inactive.");
+  ok(profilerPanel?.hasAttribute("visible"), "panel should be open");
+  ok(!isActive(), "profiler should still be inactive");
+  await getElementByLabel(document, "Start Recording");
+
+  info("Press Escape to close the panel.");
+  EventUtils.synthesizeKey("KEY_Escape");
+  await TestUtils.waitForCondition(() => overflowMenu.state == "closed");
+  ok(!dropmarker.hasAttribute("open"), "panel should be closed");
+
+  info("Undo the forced toolbar overflow.");
+  window.resizeTo(originalWindowWidth, window.outerHeight);
+  return TestUtils.waitForCondition(() => !navbar.hasAttribute("overflowing"));
+});
+
 add_task(async function space_key() {
   info("Test that the Space key starts and captures a profile.");