fix: divert thumbwheel for rotation rebinds even without single-tap capability

crates/openlogi-hid/src/gesture.rs

@@ -13,7 +13,8 @@
 //! it, mirroring how the CGEventTap hook handles the side buttons. The thumb
 //! wheel is special: diverting it stops native horizontal scroll, so the GUI
 //! re-synthesises scroll from the [`CapturedInput::Scroll`] deltas — the wheel
-//! is therefore only diverted when its click is actually bound.
+//! is therefore only diverted when the user's thumbwheel config leaves its
+//! defaults (click bound, rotation rebound, or sensitivity changed).
 
 use std::sync::{Arc, Mutex, PoisonError, RwLock};
 
@@ -44,8 +45,8 @@ pub enum CapturedInput {
     /// ([`ButtonId::Thumbwheel`]).
     ButtonPressed(ButtonId),
     /// Thumb-wheel rotation to re-synthesise as horizontal scroll, in the
-    /// wheel's `diverted_res` increments. Emitted only while the wheel is
-    /// diverted to capture its click.
+    /// wheel's `diverted_res` increments. Emitted while the wheel is diverted
+    /// (click bound, rotation rebound, or sensitivity changed).
     Scroll(i16),
 }
 
@@ -206,8 +207,8 @@ impl ArmedControls {
 
 /// Resolve features off the device's root and divert the controls we capture:
 /// the gesture button (raw-XY) and DPI/ModeShift buttons over `0x1b04`, and —
-/// when `capture_thumbwheel` and the wheel reports a single tap — the thumb
-/// wheel over `0x2150`. The root-feature lookup mirrors `write::open_feature`,
+/// when `capture_thumbwheel` — the thumb wheel over `0x2150`. The
+/// root-feature lookup mirrors `write::open_feature`,
 /// since hidpp 0.2's registry doesn't carry the features OpenLogi reimplements.
 async fn arm_controls(
     chan: &Arc<HidppChannel>,
@@ -273,14 +274,17 @@ async fn arm_controls(
                 false
             }
         };
-        if supports_single_tap {
-            tw.set_reporting(true, false)
-                .await
-                .map_err(|e| GestureError::Hidpp(format!("{e:?}")))?;
-            thumb = Some((tw, info.index));
-        } else {
+        // Divert whenever capture was requested: rotation rebinds and the
+        // sensitivity multiplier need the diverted event stream even on wheels
+        // that report no single-tap capability (e.g. MX Master 4) — lacking the
+        // tap only means a bound click can never fire.
+        if !supports_single_tap {
             debug!("thumb wheel reports no single tap — click not capturable");
         }
+        tw.set_reporting(true, false)
+            .await
+            .map_err(|e| GestureError::Hidpp(format!("{e:?}")))?;
+        thumb = Some((tw, info.index));
     }
 
     if !gesture_diverted && dpi_cids.is_empty() && thumb.is_none() {

crates/openlogi-hid/src/thumbwheel.rs

@@ -4,7 +4,8 @@
 //!
 //! The wheel only has two reporting modes — Native (HID scroll) or Diverted
 //! (HID++ events) — there is no "report taps but keep scrolling" mode. So the
-//! capture session diverts the wheel only when the user has bound its click,
+//! capture session diverts the wheel whenever the user's thumbwheel config
+//! leaves its defaults (click bound, rotation rebound, or sensitivity changed),
 //! and re-synthesises horizontal scroll from the rotation deltas to keep
 //! scrolling working.
 //!