fix(dirvish): move the sidebar to F9 so F11 toggles fullscreen againHEADmain

Stock Emacs binds F11 to toggle-frame-fullscreen, the key every other application uses for it. This config never rebound it, but dirvish-config's :bind put dirvish-side on F11 and shadowed the stock binding. I moved the sidebar toggle to F9, the free bare F-key: ai-term left it for M-SPC in June and the recording chord came off it today. F2 is the preview key and F5 is reserved for the debug backend, so neither was a candidate.

The org-capture F-key guard follows the command rather than the key. F9 joins its list and F11 leaves it, since a fullscreen toggle pops nothing over a capture. The tests pin the new key, the un-shadowed F11, and the guard change.

6 files changed, 112 insertions, 8 deletions

diff --git a/docs/specs/keybinding-console-safety-spec.org b/docs/specs/keybinding-console-safety-spec.org
index 5fd7d52c..9781b43a 100644
--- a/docs/specs/keybinding-console-safety-spec.org
+++ b/docs/specs/keybinding-console-safety-spec.org
@@ -846,7 +846,7 @@ have large package-managed binding lists not enumerated here.
   - [ ] M-D (dirvish-mode-map) — dwim-shell-commands-menu — (dwim-shell-config.el:934)
   - [ ] + (dirvish-mode-map) — cj/music-add-dired-selection — (music-config.el:597)
   - [ ] T (dired/dirvish-mode-map) — cj/transcribe-media-at-point — (transcription-config.el:463/467)
-  - [ ] <f11> (dirvish-mode-map) — dirvish-side — (dirvish-config.el:481)
+  - [ ] <f9> (global) — dirvish-side — (dirvish-config.el:661; F11 is stock toggle-frame-fullscreen again as of 2026-09-22)
 - [ ] Shell / terminal
   - [ ] C-r (eshell-mode-map) — cj/eshell-history-search — (eshell-config.el:202)
   - [ ] <up> (eshell-hist-mode-map) — previous-line — (eshell-config.el:99)
diff --git a/modules/dirvish-config.el b/modules/dirvish-config.el
index 6c849198..e9b9fde6 100644
--- a/modules/dirvish-config.el
+++ b/modules/dirvish-config.el
@@ -29,7 +29,7 @@
 ;; - S: Study — start an org-drill session on the .org file at point
 ;; - M-D (Meta-Shift-d): DWIM shell commands menu
 ;; - TAB: Toggle subtree expansion
-;; - F11: Toggle sidebar view
+;; - F9: Toggle sidebar view
 
 ;;; Code:
 
@@ -653,7 +653,13 @@ no popup frame is live."
   (("C-x d"   . dirvish)
    ("C-x C-d" . dirvish)
    ("C-x D"   . dirvish)
-   ("<f11>"   . dirvish-side)
+   ;; F9, not F11: F11 is stock Emacs's toggle-frame-fullscreen, the same key
+   ;; every other application uses, and the sidebar sat on it for years by
+   ;; shadowing that.  F9 is the free bare F-key: ai-term left it for M-SPC
+   ;; in June 2026 and the recording chord came off it on 2026-09-22.  F2 is
+   ;; the preview key (markdown-mode binds it) and F5 is reserved for the
+   ;; debug backend, so neither was a candidate.
+   ("<f9>"    . dirvish-side)
    :map dirvish-mode-map
    ("bg"      . cj/set-wallpaper)
    ("/"       . dirvish-narrow)
diff --git a/modules/org-capture-config.el b/modules/org-capture-config.el
index b7250f1e..8f5903fe 100644
--- a/modules/org-capture-config.el
+++ b/modules/org-capture-config.el
@@ -145,12 +145,16 @@ re-scanning large target files after the first successful lookup."
               :around #'cj/org-capture--set-target-location-advice))
 
 ;; --------------------------- Capture F-Key Guard -----------------------------
-;; The global popup keys (F1 dashboard sweep, F10 music, F11 dirvish-side,
+;; The global popup keys (F1 dashboard sweep, F9 dirvish-side, F10 music,
 ;; F12 terminal, M-SPC agent swap) fire even while a capture is in progress
 ;; and pop their UI over the capture popup.  org-capture-mode is a minor
 ;; mode active exactly for the capture's duration and its keymap shadows
 ;; the global map, so blocking the keys there scopes the guard precisely:
 ;; the moment the capture finalizes or aborts, the keys work again.
+;;
+;; The list follows the command, not the key.  F11 was on it while it held
+;; dirvish-side; now that F11 is the frame fullscreen toggle it pops nothing
+;; over a capture and stays usable.
 
 (defun cj/--org-capture-blocked-key ()
   "Refuse a global popup key while a capture is in progress."
@@ -160,7 +164,7 @@ re-scanning large target files after the first successful lookup."
 (defvar org-capture-mode-map)
 
 (with-eval-after-load 'org-capture
-  (dolist (key '("<f1>" "<f10>" "<f11>" "<f12>" "M-SPC"))
+  (dolist (key '("<f1>" "<f9>" "<f10>" "<f12>" "M-SPC"))
     (keymap-set org-capture-mode-map key #'cj/--org-capture-blocked-key)))
 
 ;; ----------------------- Project-Aware Capture Target ------------------------
diff --git a/tests/test-dirvish-config--side-key.el b/tests/test-dirvish-config--side-key.el
new file mode 100644
index 00000000..1f08314c
--- /dev/null
+++ b/tests/test-dirvish-config--side-key.el
@@ -0,0 +1,40 @@
+;;; test-dirvish-config--side-key.el --- dirvish-side lives on F9 -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; The sidebar toggle moved from F11 to F9 on 2026-09-22 so F11 could go back
+;; to `toggle-frame-fullscreen', the stock binding every other application
+;; shares and which the :bind had been shadowing.  F9 was the free bare
+;; F-key: ai-term left it for M-SPC in June and the recording chord came off
+;; it the same day this moved.  F2 is the preview key and F5 is reserved for
+;; the debug backend, so neither was a candidate.
+
+;;; Code:
+
+(require 'ert)
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'keybindings)
+(require 'dirvish-config)
+
+;;; Normal
+
+(ert-deftest test-dirvish-config-side-on-f9 ()
+  "Normal: F9 toggles the dirvish sidebar."
+  (should (eq (keymap-lookup global-map "<f9>") #'dirvish-side)))
+
+;;; Boundary
+
+(ert-deftest test-dirvish-config-side-not-on-f11 ()
+  "Boundary/regression: F11 no longer reaches dirvish-side, so the stock
+`toggle-frame-fullscreen' binding is no longer shadowed."
+  (should-not (eq (keymap-lookup global-map "<f11>") #'dirvish-side))
+  (should (eq (keymap-lookup global-map "<f11>") #'toggle-frame-fullscreen)))
+
+;;; Error
+
+(ert-deftest test-dirvish-config-side-target-is-a-command ()
+  "Error (positive control): the binding points at a real interactive
+command, so a keypress does not fail with a `commandp' error at press time."
+  (should (commandp (keymap-lookup global-map "<f9>"))))
+
+(provide 'test-dirvish-config--side-key)
+;;; test-dirvish-config--side-key.el ends here
diff --git a/tests/test-keybindings--fullscreen.el b/tests/test-keybindings--fullscreen.el
new file mode 100644
index 00000000..c35e398c
--- /dev/null
+++ b/tests/test-keybindings--fullscreen.el
@@ -0,0 +1,45 @@
+;;; test-keybindings--fullscreen.el --- F11 toggles frame fullscreen -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Stock Emacs binds F11 to `toggle-frame-fullscreen', the same key every
+;; other application on the desktop uses for it.  This config never rebound
+;; it; dirvish-config's :bind put dirvish-side on F11 and shadowed the stock
+;; binding for as long as that entry existed.  It moved to F9 on 2026-09-22
+;; (see test-dirvish-config--side-key.el, which pins the un-shadowing).
+;;
+;; These tests pin the foundation layer's side of that: keybindings.el must
+;; leave the stock F11 binding in place.  Only keybindings.el is loaded here
+;; on purpose.  A feature module that later claimed F11 would fail the
+;; dirvish-side regression test, not this one.
+
+;;; Code:
+
+(require 'ert)
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'keybindings)
+
+;;; Normal
+
+(ert-deftest test-keybindings-f11-toggles-fullscreen ()
+  "Normal: F11 runs `toggle-frame-fullscreen' once the foundation layer has
+loaded.  Stock Emacs provides the binding; this pins that keybindings.el does
+not unset or rebind it."
+  (should (eq (keymap-lookup global-map "<f11>") #'toggle-frame-fullscreen)))
+
+;;; Boundary
+
+(ert-deftest test-keybindings-f11-is-the-only-fullscreen-chord ()
+  "Boundary: the plain key carries it; the shifted chord is left free so a
+grazed Shift does not toggle the frame twice."
+  (should-not (eq (keymap-lookup global-map "S-<f11>")
+                  #'toggle-frame-fullscreen)))
+
+;;; Error
+
+(ert-deftest test-keybindings-f11-target-is-a-command ()
+  "Error (positive control): the target is a real interactive command, so a
+press does not fail with a `commandp' error at press time."
+  (should (commandp (keymap-lookup global-map "<f11>"))))
+
+(provide 'test-keybindings--fullscreen)
+;;; test-keybindings--fullscreen.el ends here
diff --git a/tests/test-org-capture-config-fkey-guard.el b/tests/test-org-capture-config-fkey-guard.el
index b288ce4f..c0687bb2 100644
--- a/tests/test-org-capture-config-fkey-guard.el
+++ b/tests/test-org-capture-config-fkey-guard.el
@@ -2,8 +2,10 @@
 
 ;;; Commentary:
 ;; While a capture is in progress, the global popup keys (F1 dashboard
-;; sweep, F10 music, F11 dirvish-side, F12 terminal, M-SPC agent swap)
-;; must not fire and pop UI over the capture.  org-capture-mode is a
+;; sweep, F9 dirvish-side, F10 music, F12 terminal, M-SPC agent swap)
+;; must not fire and pop UI over the capture.  F11 is deliberately not on
+;; the list: it toggles frame fullscreen, which pops nothing over the
+;; capture, so blocking it would only get in the way.  org-capture-mode is a
 ;; minor mode active exactly for the capture's duration and its keymap
 ;; shadows the global map, so the guard binds those keys there to a
 ;; blocker that signals a `user-error' naming the way out.
@@ -21,10 +23,17 @@
 
 (ert-deftest test-org-capture-fkey-guard-keys-bound ()
   "Normal: every leaking popup key is bound to the blocker in capture mode."
-  (dolist (key '("<f1>" "<f10>" "<f11>" "<f12>" "M-SPC"))
+  (dolist (key '("<f1>" "<f9>" "<f10>" "<f12>" "M-SPC"))
     (should (eq (keymap-lookup org-capture-mode-map key)
                 #'cj/--org-capture-blocked-key))))
 
+(ert-deftest test-org-capture-fkey-guard-leaves-fullscreen-alone ()
+  "Boundary: F11 (frame fullscreen) is not blocked.  It pops no UI, and
+before dirvish-side moved to F9 it was on this list only because F11 was the
+sidebar key; the entry must follow the command, not the key."
+  (should-not (eq (keymap-lookup org-capture-mode-map "<f11>")
+                  #'cj/--org-capture-blocked-key)))
+
 (ert-deftest test-org-capture-fkey-guard-blocker-signals-user-error ()
   "Error: the blocker signals a user-error rather than doing nothing."
   (should-error (cj/--org-capture-blocked-key) :type 'user-error))