diff --git a/wgpu/gui/base.py b/wgpu/gui/base.py
index b2d92765..3ff65325 100644
--- a/wgpu/gui/base.py
+++ b/wgpu/gui/base.py
@@ -237,7 +237,9 @@ def _get_event_wait_time(self):
         target_time = self._last_event_time + 1.0 / rate
         return max(0, target_time - now)
 
-    def _handle_event_rate_limited(self, ev, call_later_func, match_keys, accum_keys):
+    def _handle_event_rate_limited(
+        self, event, call_later_func, match_keys, accum_keys
+    ):
         """Alternative `to handle_event()` for events that must be rate-limted.
         If any of the `match_keys` keys of the new event differ from the currently
         pending event, the old event is dispatched now. The `accum_keys` keys of
@@ -252,23 +254,25 @@ def _handle_event_rate_limited(self, ev, call_later_func, match_keys, accum_keys
         Subclasses that use this method must use ``_handle_event_and_flush()``
         where they would otherwise call ``handle_event()``, to preserve event order.
         """
-        event_type = ev["event_type"]
+        event_type = event["event_type"]
+        event.setdefault("time_stamp", time.perf_counter())
         # We may need to emit the old event. Otherwise, we need to update the new one.
         old = self._pending_events.get(event_type, None)
         if old:
-            if any(ev[key] != old[key] for key in match_keys):
+            if any(event[key] != old[key] for key in match_keys):
                 self.handle_event(old)
             else:
                 for key in accum_keys:
-                    ev[key] = old[key] + ev[key]
+                    event[key] = old[key] + event[key]
         # Make sure that we have scheduled a moment to handle events
         if not self._pending_events:
             call_later_func(self._get_event_wait_time(), self._handle_pending_events)
         # Store the event object
-        self._pending_events[event_type] = ev
+        self._pending_events[event_type] = event
 
     def _handle_event_and_flush(self, event):
         """Call handle_event after flushing any pending (rate-limited) events."""
+        event.setdefault("time_stamp", time.perf_counter())
         self._handle_pending_events()
         self.handle_event(event)
 
diff --git a/wgpu/gui/glfw.py b/wgpu/gui/glfw.py
index 614713f3..d68eaf60 100644
--- a/wgpu/gui/glfw.py
+++ b/wgpu/gui/glfw.py
@@ -152,8 +152,8 @@ def __init__(self, *, size=None, title=None, **kwargs):
         glfw.set_window_iconify_callback(self._window, weakbind(self._on_iconify))
 
         # User input
-        self._key_modifiers = set()
-        self._pointer_buttons = set()
+        self._key_modifiers = []
+        self._pointer_buttons = []
         self._pointer_pos = 0, 0
         self._double_click_state = {"clicks": 0}
         glfw.set_mouse_button_callback(self._window, weakbind(self._on_mouse_button))
@@ -323,10 +323,14 @@ def _on_mouse_button(self, window, but, action, mods):
 
         if action == glfw.PRESS:
             event_type = "pointer_down"
-            self._pointer_buttons.add(button)
+            buttons = set(self._pointer_buttons)
+            buttons.add(button)
+            self._pointer_buttons = list(sorted(buttons))
         elif action == glfw.RELEASE:
             event_type = "pointer_up"
-            self._pointer_buttons.discard(button)
+            buttons = set(self._pointer_buttons)
+            buttons.discard(button)
+            self._pointer_buttons = list(sorted(buttons))
         else:
             return
 
@@ -426,6 +430,7 @@ def _on_scroll(self, window, dx, dy):
             "dy": -100.0 * dy,
             "x": self._pointer_pos[0],
             "y": self._pointer_pos[1],
+            "buttons": list(self._pointer_buttons),
             "modifiers": list(self._key_modifiers),
         }
         match_keys = {"modifiers"}
@@ -438,11 +443,15 @@ def _on_key(self, window, key, scancode, action, mods):
         if action == glfw.PRESS:
             event_type = "key_down"
             if modifier:
-                self._key_modifiers.add(modifier)
+                modifiers = set(self._key_modifiers)
+                modifiers.add(modifier)
+                self._key_modifiers = list(sorted(modifiers))
         elif action == glfw.RELEASE:
             event_type = "key_up"
             if modifier:
-                self._key_modifiers.discard(modifier)
+                modifiers = set(self._key_modifiers)
+                modifiers.discard(modifier)
+                self._key_modifiers = list(sorted(modifiers))
         else:  # glfw.REPEAT
             return
 
diff --git a/wgpu/gui/qt.py b/wgpu/gui/qt.py
index d429e803..2fa763fe 100644
--- a/wgpu/gui/qt.py
+++ b/wgpu/gui/qt.py
@@ -253,8 +253,8 @@ def _mouse_event(self, event_type, event, touches=True):
         if touches:
             ev.update(
                 {
-                    "ntouches": 0,  # TODO
-                    "touches": {},  # TODO
+                    "ntouches": 0,
+                    "touches": {},  # TODO: Qt touch events
                 }
             )
 
@@ -285,6 +285,11 @@ def wheelEvent(self, event):  # noqa: N802
             for mod in MODIFIERS_MAP.keys()
             if mod & event.modifiers()
         ]
+        buttons = [
+            BUTTON_MAP[button]
+            for button in BUTTON_MAP.keys()
+            if button & event.buttons()
+        ]
 
         ev = {
             "event_type": "wheel",
@@ -292,6 +297,7 @@ def wheelEvent(self, event):  # noqa: N802
             "dy": -event.angleDelta().y(),
             "x": event.position().x(),
             "y": event.position().y(),
+            "buttons": buttons,
             "modifiers": modifiers,
         }
         match_keys = {"modifiers"}