diff --git a/src/lib/components/Toolbar.svelte b/src/lib/components/Toolbar.svelte
index cf856e8..310232b 100644
--- a/src/lib/components/Toolbar.svelte
+++ b/src/lib/components/Toolbar.svelte
@@ -502,8 +502,13 @@
 
   /* Sits below the scrolling gallery (margins cancel the dropdown's padding) so it
      is reachable without scrolling to the last style. */
-  .manage {
+  /* Qualified with .ol-option: that rule sits further down the sheet, so at equal
+     specificity its width/padding/hover would win over this one's. */
+  .ol-option.manage {
     flex-shrink: 0;
+    /* auto, so the negative margins bleed the row to both panel edges instead of
+       pushing a 100%-wide box 4px past the right one. */
+    width: auto;
     margin: 2px -2px -2px;
     padding: 0.45rem 0.6rem;
     gap: 0.45rem;
@@ -520,7 +525,7 @@
     flex-shrink: 0;
   }
 
-  .manage:hover {
+  .ol-option.manage:hover {
     background: color-mix(in srgb, var(--color-primary) 16%, var(--color-surface));
   }
 
diff --git a/src/lib/components/ToolbarExpanded.svelte b/src/lib/components/ToolbarExpanded.svelte
index 107496d..f5d566e 100644
--- a/src/lib/components/ToolbarExpanded.svelte
+++ b/src/lib/components/ToolbarExpanded.svelte
@@ -9,8 +9,7 @@
   import LinkDialog from './LinkDialog.svelte';
   import { OPEN_LINK_DIALOG_EVENT } from '../editor/extensions/link';
   import {
-    CANDIDATE_FONTS,
-    detectAvailableFonts,
+    detectInstalledFonts,
     queryLocalFontsIfAllowed,
     supportsLocalFontAccess,
   } from '../utils/fontDetect';
@@ -46,7 +45,6 @@
   let recentFonts = $state<string[]>([]);
   let detectedFonts = $state<string[]>([]);
   let allInstalledFonts = $state<string[] | null>(null);
-  let detectionRan = false;
   const localFontAccessSupported =
     typeof window !== 'undefined' && supportsLocalFontAccess();
 
@@ -64,19 +62,8 @@
     try { localStorage.setItem(RECENT_FONTS_KEY, JSON.stringify(fonts)); } catch { /* quota or disabled */ }
   }
 
-  // The bundled metric-twin @font-faces (Calibri/Arial/Cambria/Courier New) only
-  // load on first use; force them so canvas measurement can see them as available.
-  const BUNDLED_TWINS = ['Calibri', 'Arial', 'Cambria', 'Courier New'];
-
   async function ensureDetectionRan() {
-    if (detectionRan) return;
-    detectionRan = true;
-    if (typeof document !== 'undefined' && document.fonts) {
-      try {
-        await Promise.all(BUNDLED_TWINS.map((f) => document.fonts.load(`12px "${f}"`)));
-      } catch { /* detect with whatever loaded */ }
-    }
-    detectedFonts = detectAvailableFonts(CANDIDATE_FONTS);
+    detectedFonts = await detectInstalledFonts();
   }
 
   onMount(() => {
diff --git a/src/lib/utils/fontDetect.ts b/src/lib/utils/fontDetect.ts
index d200e59..1708c4b 100644
--- a/src/lib/utils/fontDetect.ts
+++ b/src/lib/utils/fontDetect.ts
@@ -135,6 +135,23 @@ export async function unavailableFonts(families: Iterable<string>): Promise<stri
   return missing;
 }
 
+// One canvas measurement per candidate adds up to a frame-eating task, and the font
+// picker remounts on every toolbar expand — so detect once per page load. The bundled
+// @font-face twins only load on first use; force them so they measure as available.
+let detection: Promise<string[]> | null = null;
+
+export function detectInstalledFonts(): Promise<string[]> {
+  detection ??= (async () => {
+    if (typeof document !== 'undefined' && document.fonts) {
+      try {
+        await Promise.all(BUNDLED_FONTS.map((f) => document.fonts.load(`12px "${f}"`)));
+      } catch { /* detect with whatever loaded */ }
+    }
+    return detectAvailableFonts(CANDIDATE_FONTS);
+  })();
+  return detection;
+}
+
 interface LocalFontData { family: string }
 interface QueryLocalFontsWindow {
   queryLocalFonts?: () => Promise<LocalFontData[]>;