spotlight on ctrl+space, theme browser on ctrl+shift+up/down, no backdrop behind the theme list

src/workspaces/theme/src/useThemeKeys.ts

@@ -9,7 +9,7 @@ import type { ThemeId } from './themes';
  *
  *   ctrl+shift+→        next theme, from anywhere, no UI
  *   ctrl+shift+←        previous theme
- *   ctrl+shift+space    open the list, then browse it
+ *   ctrl+shift+↑/↓      open the list, then browse it
  *   ctrl+shift+f        star or unstar the current theme, from anywhere
  *
  * One modifier for all three, which took some choosing. `ctrl+alt+arrows` switches WORKSPACE on GNOME and
@@ -78,18 +78,22 @@ export function useThemeKeys(options: ThemeKeysOptions = {}) {
     const onKeyDown = (event: KeyboardEvent) => {
       const { themeId: current, focused: focus, open: isOpen } = state.current;
 
-      // Toggle the list. `ctrl+alt+space` is still accepted alongside `ctrl+shift+space` — it is what this
-      // shipped with first, and fingers are quicker to learn than to unlearn.
-      if (event.ctrlKey && (event.shiftKey || event.altKey) && event.code === 'Space') {
+      // Toggle the list. Vertical arrows on the SAME modifier as the horizontal cycle — one family:
+      // `ctrl+shift+←/→` steps the theme, `ctrl+shift+↑/↓` opens the browse. Was `ctrl+shift+space`
+      // (with a `ctrl+alt+space` legacy) until 2026-08-25; both space chords are gone, not kept as
+      // aliases, because `ctrl+space` became Spotlight the same day and space chords near it invite
+      // the wrong reflex.
+      if (event.ctrlKey && event.shiftKey && !event.altKey && (event.key === 'ArrowUp' || event.key === 'ArrowDown')) {
         event.preventDefault();
         /*
           Two problems solved by two lines, and both were reported from the same keystroke.
 
           `stopPropagation` stops the header's dropdown ALSO opening. The theme pill is a Radix
-          DropdownMenuTrigger, and a focused trigger opens on Space — so if the pill happened to have focus,
-          the chord opened the overlay and the menu behind it. React attaches its handlers at the root, which
-          bubbles before window, so the trigger saw the key first no matter what this listener did with it.
-          This listener now runs in the CAPTURE phase and stops the event dead.
+          DropdownMenuTrigger, and a focused trigger opens on ArrowDown (it did on Space too, when Space
+          was the chord) — so if the pill happened to have focus, the chord opened the overlay and the
+          menu behind it. React attaches its handlers at the root, which bubbles before window, so the
+          trigger saw the key first no matter what this listener did with it. This listener now runs in
+          the CAPTURE phase and stops the event dead.
 
           The blur stops the overlay opening with focus still in a text field, which made j/k/l do nothing:
           the guard below correctly refuses to steal keys from an input, and the input never lost focus.