fix(client): re-assert host mouse modes after a terminal reconnect

src/client/mod.rs

@@ -566,6 +566,16 @@ fn set_mouse_capture(enabled: bool) -> io::Result<()> {
     }
 }
 
+/// Re-apply the host mouse mode set after the host surface may have been
+/// re-created underneath us. `set_mouse_capture` clears host mouse reporting
+/// first, so this also drops a tracking mode that a reconnect restored behind
+/// herdr's back in an encoding the client cannot parse.
+fn refresh_host_mouse_capture(enabled: bool) {
+    if let Err(err) = set_mouse_capture(enabled) {
+        warn!(err = %err, "failed to re-assert host mouse capture");
+    }
+}
+
 fn restore_terminal_state(
     reset_modify_other_keys: bool,
     reset_host_color_scheme_reports: bool,
@@ -1452,6 +1462,9 @@ async fn run_client_loop(
                     ) {
                         state.request_repaint();
                     }
+                    if crate::raw_input::events_require_host_mode_refresh(&events) {
+                        refresh_host_mouse_capture(state.mouse_capture_active);
+                    }
                     if crate::raw_input::events_require_host_terminal_theme_query(&events) {
                         query_host_terminal_theme();
                     }
@@ -1527,6 +1540,9 @@ async fn run_client_loop(
                 ) {
                     state.request_repaint();
                 }
+                if crate::raw_input::events_require_host_mode_refresh(&raw_events) {
+                    refresh_host_mouse_capture(state.mouse_capture_active);
+                }
                 let msg = ClientMessage::InputEvents { events };
                 if let Err(e) = write_to_server(&mut write_stream, &msg) {
                     return Err(ClientError::ConnectionLost(e));
@@ -1536,6 +1552,10 @@ async fn run_client_loop(
                 state.reported_size = (new_cols, new_rows);
                 // Resizing invalidates the host-side blit baseline.
                 state.request_repaint();
+                // A reconnect re-syncs the terminal size before the user touches
+                // anything, so this usually restores the mode set before the
+                // first stray mouse report can leak into a pane.
+                refresh_host_mouse_capture(state.mouse_capture_active);
                 let msg = ClientMessage::Resize {
                     cols: new_cols,
                     rows: new_rows,

src/raw_input.rs

@@ -578,6 +578,21 @@ pub(crate) fn events_require_host_surface_redraw(
             .any(|event| matches!(event, RawInputEvent::OuterFocusGained))
 }
 
+/// A host terminal can be re-created underneath a live client. Web VS Code, for
+/// example, restores a reconnected terminal from a serialized snapshot that
+/// brings back mouse tracking without the SGR encoding herdr asked for, so every
+/// mouse report then arrives in an encoding the client cannot parse and leaks
+/// into the focused pane as text. Regained focus is the earliest signal that the
+/// surface may be new, so use it to re-assert the host terminal modes.
+///
+/// This is deliberately independent of `redraw_on_focus_gained`: that option
+/// only controls repainting, while a stale mode set corrupts input regardless.
+pub(crate) fn events_require_host_mode_refresh(events: &[RawInputEvent]) -> bool {
+    events
+        .iter()
+        .any(|event| matches!(event, RawInputEvent::OuterFocusGained))
+}
+
 #[cfg(any(not(windows), test))]
 pub(crate) fn events_require_host_terminal_theme_query(events: &[RawInputEvent]) -> bool {
     events
@@ -1484,6 +1499,18 @@ mod tests {
         assert!(!events_require_host_surface_redraw(&events, true));
     }
 
+    #[test]
+    fn outer_focus_gained_requests_host_mode_refresh() {
+        let events = parse_raw_input_bytes_sync(b"\x1b[I");
+        assert!(events_require_host_mode_refresh(&events));
+
+        let events = parse_raw_input_bytes_sync(b"\x1b[O");
+        assert!(!events_require_host_mode_refresh(&events));
+
+        let events = parse_raw_input_bytes_sync(b"a");
+        assert!(!events_require_host_mode_refresh(&events));
+    }
+
     #[test]
     fn parses_ghostty_color_scheme_reports() {
         for bytes in [