fix: disambiguate shifted punctuation keybinds

refs #2674

docs/next/CHANGELOG.md

@@ -19,6 +19,7 @@
 - Experimental pane graphics now support bounded named layers, acknowledged full-RGBA primary-layer direct file frames on audited local terminals, owned BGRA fallback, exact pixel mouse input, and placement-only resize replay.
 
 ### Fixed
+- Prefix keybindings now disambiguate layout-aware shifted punctuation, so a shifted `\` no longer triggers `prefix+|` on keyboard layouts where the same key produces both characters. (#2674)
 - OpenCode panes now track the root conversation selected in their own TUI for native restore without adopting activity from attached clients. (#2450)
 - Server stop requests now bypass pane and API traffic, preventing busy sessions from blocking shutdown or admitting a client while shutdown is pending. (#2612)
 - Fish `Ctrl+Alt` keybindings now work in panes after legacy Alt-prefixed control bytes are decoded with both modifiers. (#2514)

src/app/input/navigate.rs

@@ -2815,6 +2815,39 @@ resize_pane_left = "prefix+shift+left"
         assert_eq!(action, Some(NavigateAction::LastPane));
     }
 
+    #[test]
+    fn shifted_backslash_layout_prefers_horizontal_split_binding() {
+        let config: Config = toml::from_str(
+            r#"
+[keys]
+split_vertical = "prefix+|"
+split_horizontal = 'prefix+\'
+"#,
+        )
+        .unwrap();
+        let mut state = state_with_workspaces(&["test"]);
+        state.keybinds = config.keybinds();
+        let key = crate::input::parse_terminal_key_sequence("\x1b[124:92;2:1u").unwrap();
+        assert_eq!(key.code, KeyCode::Char('|'));
+        assert_eq!(key.modifiers, KeyModifiers::SHIFT);
+        assert_eq!(key.shifted_codepoint, Some('\\' as u32));
+        assert!(state.keybinds.split_horizontal.matches_prefix_key(&key));
+        assert!(!state.keybinds.split_vertical.matches_prefix_key(&key));
+
+        assert_eq!(
+            action_for_key(&state, key, BindingDispatch::Prefix),
+            Some(NavigateAction::SplitHorizontal)
+        );
+        assert_eq!(
+            action_for_key(
+                &state,
+                TerminalKey::new(KeyCode::Char('|'), KeyModifiers::empty()),
+                BindingDispatch::Prefix,
+            ),
+            Some(NavigateAction::SplitVertical)
+        );
+    }
+
     #[test]
     fn prefix_tab_override_can_map_to_last_pane() {
         let config: Config = toml::from_str(

src/config/keybinds.rs

@@ -1437,8 +1437,8 @@ fn shifted_char_matches_expected(
     let KeyCode::Char(expected) = expected_code else {
         return false;
     };
-    if shifted_codepoint.and_then(char::from_u32) == Some(expected) {
-        return true;
+    if let Some(shifted) = shifted_codepoint.and_then(char::from_u32) {
+        return shifted == expected;
     }
     matches!(actual_code, KeyCode::Char(actual) if actual == expected && is_shifted_punctuation(expected))
 }