diff --git a/crates/ui-egui/src/grid.rs b/crates/ui-egui/src/grid.rs
index 28afbdd36..5b55462d4 100644
--- a/crates/ui-egui/src/grid.rs
+++ b/crates/ui-egui/src/grid.rs
@@ -2716,7 +2716,9 @@ fn keyboard(app: &mut SheetApp, ctx: &egui::Context, resp: &egui::Response, geo:
                     }
                     Key::F9 => app.run_or_alert("formulas.calculateNow", json!({})),
                     Key::F4 if !cmd => {}
-                    _ if cmd => crate::ribbon::shortcut(app, key, m),
+                    _ if cmd && !crate::keymap::altgr_text(ctx, m, ctx.os() == egui::os::OperatingSystem::Mac) => {
+                        crate::ribbon::shortcut(app, key, m)
+                    }
                     _ => {}
                 }
             }
diff --git a/crates/ui-egui/src/keymap.rs b/crates/ui-egui/src/keymap.rs
index 032db1a2d..92f7093d7 100644
--- a/crates/ui-egui/src/keymap.rs
+++ b/crates/ui-egui/src/keymap.rs
@@ -162,12 +162,16 @@ pub fn lookup(key: Key, physical: Option<Key>, m: Modifiers, mac: bool) -> Optio
     })
 }
 
+/// AltGr arrives as Ctrl+Alt on Windows: a key that also typed a character (AltGr+= is `~` on a German
+/// layout; a user-defined Ctrl+Alt+A hotkey may type `ä`) is text, not a shortcut.
+pub(crate) fn altgr_text(ctx: &egui::Context, m: Modifiers, mac: bool) -> bool {
+    !mac && m.alt && m.ctrl && ctx.input(|i| i.events.iter().any(|e| matches!(e, egui::Event::Text(_))))
+}
+
 /// Handles a key press in the grid. Returns whether it was a shortcut.
 pub(crate) fn dispatch(app: &mut SheetApp, ctx: &egui::Context, key: Key, physical: Option<Key>, m: Modifiers, geo: &Geo, sh: &Sheet) -> bool {
     let mac = ctx.os() == egui::os::OperatingSystem::Mac;
-    // AltGr arrives as Ctrl+Alt on Windows: a key that also typed a character (AltGr+= is `~`
-    // on a German layout) is text, not a shortcut.
-    if !mac && m.alt && m.ctrl && ctx.input(|i| i.events.iter().any(|e| matches!(e, egui::Event::Text(_)))) {
+    if altgr_text(ctx, m, mac) {
         return false;
     }
     let Some(shortcut) = lookup(key, physical, m, mac) else { return false };
diff --git a/crates/ui-egui/tests/keyboard_shortcuts.rs b/crates/ui-egui/tests/keyboard_shortcuts.rs
index 78bc966f5..d87f31ad5 100644
--- a/crates/ui-egui/tests/keyboard_shortcuts.rs
+++ b/crates/ui-egui/tests/keyboard_shortcuts.rs
@@ -247,3 +247,14 @@ fn alt_equals_autosum_does_not_also_type_the_equals_sign() {
     alt_equals(&mut h);
     assert_eq!(h.state().editor.as_ref().map(|e| e.text.clone()).as_deref(), Some("=SUM()"));
 }
+
+#[test]
+fn ctrl_alt_letter_that_typed_text_is_not_select_all() {
+    let mut h = harness(book("B2"));
+    let ctrl_alt = Modifiers { alt: true, ..CTRL };
+    h.input_mut().events.push(Event::Key { key: Key::A, physical_key: Some(Key::A), pressed: true, repeat: false, modifiers: ctrl_alt });
+    h.input_mut().events.push(Event::Text("\u{e4}".into()));
+    h.run_steps(2);
+    assert_eq!(h.state().session.active().unwrap().selection.current().a1(), "B2");
+    assert_eq!(h.state().editor.as_ref().unwrap().text, "\u{e4}");
+}
diff --git a/docs/ui-parity.md b/docs/ui-parity.md
index aaa6a0e82..709d73da9 100644
--- a/docs/ui-parity.md
+++ b/docs/ui-parity.md
@@ -130,7 +130,8 @@ otherwise. Number-format and border keys match the physical key (Ctrl+Shift+4, w
 | — | Cmd+= (calculate), Cmd+T (references while editing; F4 works), Shift+F7, Cmd+Shift+L | Mac-only extras | missing (Cmd+= is egui's zoom key; no thesaurus or Modify Cell Style) |
 
 On Windows, AltGr arrives as Ctrl+Alt: a Ctrl+Alt key that also types a character is treated as
-text, so AltGr symbols (e.g. `~` on a German layout) never trigger a shortcut.
+text, so AltGr symbols (e.g. `~` on a German layout) and user-defined Ctrl+Alt+letter hotkeys that type
+a character (e.g. Ctrl+Alt+A for `ä`) never trigger a shortcut, Ctrl+letter ones like Select All included.
 
 ## Dialogs
 
@@ -166,6 +167,7 @@ scrollbar bugs 2–4 · pixel/feel pass against observed Excel 7–12.
 | 2026-10-18 | minor | Keytip letters typed with left Alt held continue the sequence (Alt+H, O, A / Alt+H, O, I ran nothing before: Alt+letter cancelled keytips); other Alt combinations, AltGr and macOS Option are unchanged (#1846) |
 | 2026-10-13 | minor | AutoFill month patterns retain the workbook's date system, preventing shifted dates in 1904 workbooks when filling forward or backward |
 | 2026-10-16 | minor | Ctrl+Shift+A (Control+Shift+A on a Mac) after a function name, or after its `(`, inserts the argument names and the closing parenthesis, as in Excel; one Undo in the editor takes them back |
+| 2026-10-17 | minor | A Ctrl+Alt+letter key that types a character (a user-defined Windows hotkey such as Ctrl+Alt+A for `ä`) types it instead of running the Ctrl+letter shortcut, e.g. Select All (#1530) |
 | 2026-10-12 | minor | The File view's recent list tells when each workbook was last changed, read off the UI thread |
 | 2026-10-13 | minor | Horizontal scrollbar in the sheet tab bar: drag, track click pages, frozen columns excluded from the page (#840) |
 | 2026-10-12 | minor | Ctrl+wheel zoom steps along a ladder of percentages about 20% apart that never skips 100%, gliding to each step with animations on, so a notch out undoes a notch in (it drifted: 100 → 122 → 101); Excel steps 15 points, see decisions.md |