fix(tui): default composer_arrows_scroll on when mouse capture is off

On platforms where mouse capture is disabled by default (Windows CMD /
legacy conhost), the terminal sends mouse-wheel events as Up/Down arrow-
key sequences.  Without composer_arrows_scroll those sequences cycle the
input history instead of scrolling the transcript (#1443).

Set the default for composer_arrows_scroll to !use_mouse_capture so that
terminals that forward wheel events as arrows get page-scrolling out of the
box, while terminals with real mouse capture (Windows Terminal, Linux, macOS)
keep the existing history-navigation default.

The explicit [tui] composer_arrows_scroll config key still overrides the
derived default in both directions.

Also enable mouse capture by default for ConEmu/Cmder (ConEmuPID env var),
which handles VT mouse-mode reporting cleanly, giving those users in-app
scrolling without needing --mouse-capture.

Fixes #1443

Signed-off-by: CrepuscularIRIS <serenitygp@qq.com>

crates/tui/src/main.rs

@@ -3648,12 +3648,14 @@ fn should_use_alt_screen(_cli: &Cli, _config: &Config) -> bool {
 fn should_use_mouse_capture(cli: &Cli, config: &Config, use_alt_screen: bool) -> bool {
     let terminal_emulator = std::env::var("TERMINAL_EMULATOR").ok();
     let wt_session = std::env::var("WT_SESSION").ok().filter(|s| !s.is_empty());
+    let conemu_pid = std::env::var("ConEmuPID").ok().filter(|s| !s.is_empty());
     should_use_mouse_capture_with(
         cli,
         config,
         use_alt_screen,
         terminal_emulator.as_deref(),
         wt_session.as_deref(),
+        conemu_pid.as_deref(),
     )
 }
 
@@ -3663,6 +3665,7 @@ fn should_use_mouse_capture_with(
     use_alt_screen: bool,
     terminal_emulator: Option<&str>,
     wt_session: Option<&str>,
+    conemu_pid: Option<&str>,
 ) -> bool {
     if !use_alt_screen || cli.no_mouse_capture {
         return false;
@@ -3674,15 +3677,16 @@ fn should_use_mouse_capture_with(
         .tui
         .as_ref()
         .and_then(|tui| tui.mouse_capture)
-        .unwrap_or_else(|| default_mouse_capture_enabled(terminal_emulator, wt_session))
+        .unwrap_or_else(|| default_mouse_capture_enabled(terminal_emulator, wt_session, conemu_pid))
 }
 
 /// Whether to enable terminal mouse capture by default for this platform/host.
 ///
 /// On Windows the default depends on the host: Windows Terminal (which sets
-/// `WT_SESSION`) handles mouse-mode reporting cleanly, so default-on there
-/// gives users in-app text selection and keeps the application's selection
-/// clamped to the transcript area (#1169). Legacy conhost stays default-off
+/// `WT_SESSION`) and ConEmu/Cmder (which set `ConEmuPID`) handle mouse-mode
+/// reporting cleanly, so default-on there gives users in-app text selection
+/// and keeps the application's selection clamped to the transcript area
+/// (#1169). Legacy conhost (CMD without either env var) stays default-off
 /// because its mouse-mode reporting can leak SGR escape sequences as raw
 /// text into the composer (#878 / #898).
 ///
@@ -3693,9 +3697,10 @@ fn should_use_mouse_capture_with(
 fn default_mouse_capture_enabled(
     terminal_emulator: Option<&str>,
     wt_session: Option<&str>,
+    conemu_pid: Option<&str>,
 ) -> bool {
     if cfg!(windows) {
-        return wt_session.is_some();
+        return wt_session.is_some() || conemu_pid.is_some();
     }
     if matches!(terminal_emulator, Some(t) if t.eq_ignore_ascii_case("JetBrains-JediTerm")) {
         return false;
@@ -4661,21 +4666,21 @@ mod terminal_mode_tests {
         let config = Config::default();
 
         assert!(should_use_mouse_capture_with(
-            &cli, &config, true, None, None
+            &cli, &config, true, None, None, None
         ));
     }
 
     #[test]
     #[cfg(windows)]
     fn mouse_capture_defaults_off_on_legacy_windows_console() {
-        // Legacy conhost (no `WT_SESSION`) keeps the v0.8.x default-off
-        // behavior: mouse-mode reporting on legacy console can leak SGR
-        // escapes into the composer.
+        // Legacy conhost (no `WT_SESSION` and no `ConEmuPID`) keeps the
+        // v0.8.x default-off behavior: mouse-mode reporting on legacy console
+        // can leak SGR escapes into the composer.
         let cli = parse_cli(&["deepseek"]);
         let config = Config::default();
 
         assert!(!should_use_mouse_capture_with(
-            &cli, &config, true, None, None
+            &cli, &config, true, None, None, None
         ));
     }
 
@@ -4696,6 +4701,25 @@ mod terminal_mode_tests {
             true,
             None,
             Some("{a3a3b3a8-aa00-0000-0000-000000000000}"),
+            None,
+        ));
+    }
+
+    // ConEmu/Cmder sets `ConEmuPID` and handles VT mouse-mode reporting
+    // cleanly; default mouse capture on there so users get in-app scrolling.
+    #[test]
+    #[cfg(windows)]
+    fn mouse_capture_defaults_on_in_conemu() {
+        let cli = parse_cli(&["deepseek"]);
+        let config = Config::default();
+
+        assert!(should_use_mouse_capture_with(
+            &cli,
+            &config,
+            true,
+            None,
+            None,
+            Some("12345"),
         ));
     }
 
@@ -4705,7 +4729,7 @@ mod terminal_mode_tests {
         let config = Config::default();
 
         assert!(!should_use_mouse_capture_with(
-            &cli, &config, true, None, None
+            &cli, &config, true, None, None, None
         ));
     }
 
@@ -4726,7 +4750,7 @@ mod terminal_mode_tests {
         };
 
         assert!(!should_use_mouse_capture_with(
-            &cli, &config, true, None, None
+            &cli, &config, true, None, None, None
         ));
     }
 
@@ -4736,7 +4760,7 @@ mod terminal_mode_tests {
         let config = Config::default();
 
         assert!(should_use_mouse_capture_with(
-            &cli, &config, true, None, None
+            &cli, &config, true, None, None, None
         ));
     }
 
@@ -4757,7 +4781,7 @@ mod terminal_mode_tests {
         };
 
         assert!(should_use_mouse_capture_with(
-            &cli, &config, true, None, None
+            &cli, &config, true, None, None, None
         ));
     }
 
@@ -4767,7 +4791,7 @@ mod terminal_mode_tests {
         let config = Config::default();
 
         assert!(!should_use_mouse_capture_with(
-            &cli, &config, false, None, None
+            &cli, &config, false, None, None, None
         ));
     }
 
@@ -4789,6 +4813,7 @@ mod terminal_mode_tests {
             true,
             Some("JetBrains-JediTerm"),
             None,
+            None,
         ));
     }
 
@@ -4805,6 +4830,7 @@ mod terminal_mode_tests {
             true,
             Some("jetbrains-jediterm"),
             None,
+            None,
         ));
     }
 
@@ -4819,6 +4845,7 @@ mod terminal_mode_tests {
             true,
             Some("JetBrains-JediTerm"),
             None,
+            None,
         ));
     }
 
@@ -4844,6 +4871,7 @@ mod terminal_mode_tests {
             true,
             Some("JetBrains-JediTerm"),
             None,
+            None,
         ));
     }
 }

crates/tui/src/tui/app.rs

@@ -786,7 +786,10 @@ pub struct App {
     pub use_alt_screen: bool,
     pub use_mouse_capture: bool,
     /// When true, plain Up/Down on an empty composer scroll the transcript
-    /// instead of navigating input history (#1117 opt-in).
+    /// instead of navigating input history.  Defaults to `true` when mouse
+    /// capture is off: terminals that convert mouse-wheel events to arrow-key
+    /// sequences (e.g. Windows CMD without `WT_SESSION`) get page-scrolling
+    /// without any explicit config (#1443).
     pub composer_arrows_scroll: bool,
     pub use_bracketed_paste: bool,
     pub use_paste_burst_detection: bool,
@@ -1542,7 +1545,7 @@ impl App {
                 .tui
                 .as_ref()
                 .and_then(|tui| tui.composer_arrows_scroll)
-                .unwrap_or(false),
+                .unwrap_or(!use_mouse_capture),
         }
     }
 

crates/tui/src/tui/ui/tests.rs

@@ -1022,6 +1022,30 @@ fn create_test_app() -> App {
     App::new(options, &Config::default())
 }
 
+fn create_test_options() -> TuiOptions {
+    TuiOptions {
+        model: "deepseek-v4-pro".to_string(),
+        workspace: PathBuf::from("."),
+        config_path: None,
+        config_profile: None,
+        allow_shell: false,
+        use_alt_screen: true,
+        use_mouse_capture: false,
+        use_bracketed_paste: true,
+        max_subagents: 1,
+        skills_dir: PathBuf::from("."),
+        memory_path: PathBuf::from("memory.md"),
+        notes_path: PathBuf::from("notes.txt"),
+        mcp_config_path: PathBuf::from("mcp.json"),
+        use_memory: false,
+        start_in_agent_mode: false,
+        skip_onboarding: false,
+        yolo: false,
+        resume_session_id: None,
+        initial_input: None,
+    }
+}
+
 fn text_message(role: &str, text: &str) -> Message {
     Message {
         role: role.to_string(),
@@ -4567,9 +4591,12 @@ fn checklist_write_renders_dedicated_card() {
 #[test]
 fn history_arrow_handles_empty_input() {
     let mut app = create_test_app();
+    // Explicitly disable arrows-scroll so this test covers the
+    // history-navigation path regardless of the mouse-capture default.
+    app.composer_arrows_scroll = false;
     app.input_history.push("previous prompt".to_string());
 
-    // Default: empty composer Up navigates input history (#1117).
+    // With arrows-scroll off: empty composer Up navigates input history (#1117).
     assert!(handle_composer_history_arrow(
         &mut app,
         KeyEvent::new(KeyCode::Up, KeyModifiers::NONE),
@@ -4582,6 +4609,9 @@ fn history_arrow_handles_empty_input() {
 #[test]
 fn history_arrow_handles_whitespace_input() {
     let mut app = create_test_app();
+    // Explicitly disable arrows-scroll so this test covers the
+    // history-navigation path regardless of the mouse-capture default.
+    app.composer_arrows_scroll = false;
     app.input = "   ".to_string();
     app.cursor_position = app.input.chars().count();
     app.input_history.push("previous prompt".to_string());
@@ -4660,6 +4690,56 @@ fn composer_arrows_scroll_nonempty_still_navigates_history() {
     assert_eq!(app.input, "previous prompt");
 }
 
+// #1443: when mouse capture is off (e.g. Windows CMD), arrow-scroll
+// must default to true so mouse-wheel events (sent as arrow keys by
+// the terminal) scroll the transcript rather than cycling history.
+#[test]
+fn composer_arrows_scroll_defaults_true_without_mouse_capture() {
+    let options = TuiOptions {
+        use_mouse_capture: false,
+        ..create_test_options()
+    };
+    let app = App::new(options, &Config::default());
+    assert!(
+        app.composer_arrows_scroll,
+        "arrows-scroll must default to true when mouse capture is off"
+    );
+}
+
+#[test]
+fn composer_arrows_scroll_defaults_false_with_mouse_capture() {
+    let options = TuiOptions {
+        use_mouse_capture: true,
+        ..create_test_options()
+    };
+    let app = App::new(options, &Config::default());
+    assert!(
+        !app.composer_arrows_scroll,
+        "arrows-scroll must default to false when mouse capture is on"
+    );
+}
+
+#[test]
+fn composer_arrows_scroll_config_overrides_default() {
+    let config = Config {
+        tui: Some(crate::config::TuiConfig {
+            composer_arrows_scroll: Some(false),
+            ..Default::default()
+        }),
+        ..Config::default()
+    };
+    // Even with mouse_capture off, explicit config=false wins.
+    let options = TuiOptions {
+        use_mouse_capture: false,
+        ..create_test_options()
+    };
+    let app = App::new(options, &config);
+    assert!(
+        !app.composer_arrows_scroll,
+        "explicit config=false must override the mouse-capture-derived default"
+    );
+}
+
 #[test]
 fn notification_settings_tui_always_keeps_configured_method_no_threshold() {
     let config = Config {