diff --git a/frontend/src/lib/settings.ts b/frontend/src/lib/settings.ts
index 51a8abc..c33a3c4 100644
--- a/frontend/src/lib/settings.ts
+++ b/frontend/src/lib/settings.ts
@@ -212,6 +212,15 @@ const LEGACY_GEKANATOR_BACKGROUND_MOTION_STORAGE_KEY =
 const LEGACY_MIGRATED_THEME_ID = 'custom:legacy-migrated'
 
 
+const createCustomThemeId = (): `custom:${ string }` => {
+  const randomPart =
+      globalThis.crypto?.randomUUID?.()
+      ?? `${ Date.now ().toString (36) }-${ Math.random ().toString (36).slice (2) }`
+
+  return `custom:${ randomPart }`
+}
+
+
 export const fetchUserSettings = async (): Promise<UserSettings> => {
   const raw = await apiGet<{
       theme:               UserSettings['theme']
@@ -567,7 +576,7 @@ export const createCustomThemeFromBase = (
     baseTheme:   BuiltinThemeId,
     tokens?:     ThemeTokens,
 ): CustomClientTheme => {
-  const id = `custom:${ crypto.randomUUID () }` as ThemeId
+  const id = createCustomThemeId ()
   return {
       id,
       name: themeCopyName (baseTheme),
diff --git a/frontend/src/pages/users/SettingPage.tsx b/frontend/src/pages/users/SettingPage.tsx
index 9d1af16..7e83cc7 100644
--- a/frontend/src/pages/users/SettingPage.tsx
+++ b/frontend/src/pages/users/SettingPage.tsx
@@ -71,6 +71,7 @@ type SharedSectionProps = {
     selectedTheme:         ClientTheme
     draftTagColours:       ThemeTagColours
     onThemeChange:         (themeId: ActiveThemeId) => void
+    onEnsureEditableTheme: () => void
     onTagColourChange:     (category: Category, colour: string) => void
     onResetAllTagColours:  () => void
     onResetTagColour:      (category: Category) => void
@@ -252,6 +253,7 @@ const ThemeSection: FC<SharedSectionProps> = ({
     draftCustomThemes,
     selectedTheme,
     draftTagColours,
+    onEnsureEditableTheme,
     onResetAllTagColours,
     onResetTagColour,
     onTagColourChange,
@@ -331,6 +333,8 @@ const ThemeSection: FC<SharedSectionProps> = ({
 		      <input
 			  type="color"
 			  value={draftTagColours[category]}
+			  onPointerDown={onEnsureEditableTheme}
+			  onFocus={onEnsureEditableTheme}
 			  onChange={ev => onTagColourChange (category, ev.target.value)}
 			  className="h-10 w-16 cursor-pointer rounded border border-border
 				     bg-transparent p-1"/>
@@ -514,6 +518,21 @@ const SettingPage: FC<Props> = ({ user, setUser }) => {
     }
   }
 
+  const handleEnsureEditableTheme = (): {
+      activeThemeId: ActiveThemeId
+      customThemes:  Record<string, CustomClientTheme>
+  } => {
+    const editable = ensureEditableCustomTheme ()
+
+    if (editable.activeThemeId !== draftActiveThemeId
+	|| editable.customThemes !== draftCustomThemes)
+      {
+	applyDraftThemeSelection (editable.activeThemeId, editable.customThemes)
+      }
+
+    return editable
+  }
+
   const handleTabKeyDown = (event: KeyboardEvent<HTMLButtonElement>) => {
     const currentIndex = tabs.findIndex (tab => tab.id === activeTab)
 
@@ -677,8 +696,11 @@ const SettingPage: FC<Props> = ({ user, setUser }) => {
       onThemeChange: themeId => {
 	  applyDraftThemeSelection (themeId, draftCustomThemes)
       },
+      onEnsureEditableTheme: () => {
+	  handleEnsureEditableTheme ()
+      },
       onTagColourChange: (category, colour) => {
-	  const editable = ensureEditableCustomTheme ()
+	  const editable = handleEnsureEditableTheme ()
 	  const editableTheme = editable.customThemes[editable.activeThemeId]
 	  const nextCustomThemes = {
 	      ...editable.customThemes,