Fix #9904

docs/changelog.rst

@@ -257,6 +257,8 @@ Detailed list of changes
 
 - Add an option to :opt:`focus_follows_mouse` to only switch focus on drops rather than movement (:pull:`9896`)
 
+- Fix setting :opt:`momentum_scroll` to zero not *fully* disabling momentum scrolling (:iss:`9904`)
+
 
 0.46.2 [2026-03-21]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

glfw/internal.h

@@ -917,6 +917,7 @@ void glfw_handle_scroll_event_for_momentum(_GLFWwindow *w, const GLFWScrollEvent
 #else
 #define momentum_scroll_gesture_detection_timeout_ms 0
 #endif
+bool glfw_is_momentum_scroll_enabled(void);
 
 char* _glfw_strdup(const char* source);
 

glfw/momentum-scroll.c

@@ -176,13 +176,18 @@ is_suitable_for_momentum(void) {
     );
 }
 
+bool
+glfw_is_momentum_scroll_enabled(void) {
+    return s.friction > 0;
+}
+
 void
 glfw_handle_scroll_event_for_momentum(
     _GLFWwindow *w, const GLFWScrollEvent *ev, bool stopped, bool is_finger_based
 ) {
     const bool is_synthetic_momentum_start_event = stopped && momentum_scroll_gesture_detection_timeout_ms;
     if (!w) { cancel_existing_scroll(true); return; }
-    if (!is_finger_based || ev->offset_type != GLFW_SCROLL_OFFEST_HIGHRES || s.friction < 0 || s.friction >= 1) {
+    if (!is_finger_based || ev->offset_type != GLFW_SCROLL_OFFEST_HIGHRES || !glfw_is_momentum_scroll_enabled()) {
         if (ev->x_offset != 0 || ev->y_offset != 0) _glfwInputScroll(w, ev);
         return;
     }

glfw/x11_window.c

@@ -1513,7 +1513,7 @@ handle_xi_motion_event(_GLFWwindow *window, XIDeviceEvent *de) {
             };
 
             // For high-resolution, finger-based scrolling, use timer-based momentum scrolling
-            if (d->is_finger_based && type == GLFW_SCROLL_OFFEST_HIGHRES) {
+            if (d->is_finger_based && type == GLFW_SCROLL_OFFEST_HIGHRES && glfw_is_momentum_scroll_enabled()) {
                 // Reset the timer on each scroll event
                 x11_cancel_momentum_scroll_timer();