[Windows] request_redraw example continuously generates spurious CursorMoved event

[filnet]

On master, run the request_redraw example and keep the mouse pointer inside the window.
This will continuously generate a CursorMoved event.
Note that the position is always the same.

# cargo run --example request_redraw > log.txt
    Finished dev [unoptimized + debuginfo] target(s) in 0.27s
     Running `target\debug\examples\request_redraw.exe`
NewEvents(Init)
DeviceEvent { device_id: DeviceId(DeviceId(65597)), event: Added }
DeviceEvent { device_id: DeviceId(DeviceId(720955)), event: Added }
DeviceEvent { device_id: DeviceId(DeviceId(65601)), event: Added }
DeviceEvent { device_id: DeviceId(DeviceId(720959)), event: Added }
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorEntered { device_id: DeviceId(DeviceId(0)) } }
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorMoved { device_id: DeviceId(DeviceId(0)), position: PhysicalPosition { x: 841.0, y: 434.0 }, modifiers: (empty) } }
MainEventsCleared
RedrawRequested(WindowId(WindowId(0x150bc8)))

redrawing!

RedrawEventsCleared
NewEvents(WaitCancelled { start: Instant { t: 88296.907572977s }, requested_resume: None })
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorMoved { device_id: DeviceId(DeviceId(0)), position: PhysicalPosition { x: 841.0, y: 434.0 }, modifiers: (empty) } }
MainEventsCleared
RedrawEventsCleared
NewEvents(WaitCancelled { start: Instant { t: 88297.857701111s }, requested_resume: None })
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorMoved { device_id: DeviceId(DeviceId(0)), position: PhysicalPosition { x: 841.0, y: 434.0 }, modifiers: (empty) } }
MainEventsCleared
RedrawEventsCleared
NewEvents(WaitCancelled { start: Instant { t: 88297.891609389s }, requested_resume: None })
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorMoved { device_id: DeviceId(DeviceId(0)), position: PhysicalPosition { x: 841.0, y: 434.0 }, modifiers: (empty) } }
MainEventsCleared
RedrawEventsCleared
NewEvents(WaitCancelled { start: Instant { t: 88298.884658111s }, requested_resume: None })
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorMoved { device_id: DeviceId(DeviceId(0)), position: PhysicalPosition { x: 841.0, y: 434.0 }, modifiers: (empty) } }
MainEventsCleared
RedrawEventsCleared
NewEvents(WaitCancelled { start: Instant { t: 88299.896964899s }, requested_resume: None })
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorMoved { device_id: DeviceId(DeviceId(0)), position: PhysicalPosition { x: 841.0, y: 434.0 }, modifiers: (empty) } }
MainEventsCleared
RedrawEventsCleared
NewEvents(WaitCancelled { start: Instant { t: 88300.90603008s }, requested_resume: None })
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorMoved { device_id: DeviceId(DeviceId(0)), position: PhysicalPosition { x: 841.0, y: 434.0 }, modifiers: (empty) } }
MainEventsCleared
RedrawEventsCleared
NewEvents(WaitCancelled { start: Instant { t: 88301.923038956s }, requested_resume: None })
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorMoved { device_id: DeviceId(DeviceId(0)), position: PhysicalPosition { x: 841.0, y: 434.0 }, modifiers: (empty) } }
MainEventsCleared
RedrawEventsCleared
NewEvents(WaitCancelled { start: Instant { t: 88302.915392581s }, requested_resume: None })
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorMoved { device_id: DeviceId(DeviceId(0)), position: PhysicalPosition { x: 841.0, y: 434.0 }, modifiers: (empty) } }
MainEventsCleared
RedrawEventsCleared
NewEvents(WaitCancelled { start: Instant { t: 88303.953817589s }, requested_resume: None })
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorMoved { device_id: DeviceId(DeviceId(0)), position: PhysicalPosition { x: 841.0, y: 434.0 }, modifiers: (empty) } }
MainEventsCleared
RedrawEventsCleared
NewEvents(WaitCancelled { start: Instant { t: 88304.964164733s }, requested_resume: None })
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorMoved { device_id: DeviceId(DeviceId(0)), position: PhysicalPosition { x: 841.0, y: 434.0 }, modifiers: (empty) } }
MainEventsCleared
RedrawEventsCleared
NewEvents(WaitCancelled { start: Instant { t: 88305.976293626s }, requested_resume: None })
WindowEvent { window_id: WindowId(WindowId(0x150bc8)), event: CursorMoved { device_id: DeviceId(DeviceId(0)), position: PhysicalPosition { x: 841.0, y: 434.0 }, modifiers: (empty) } }
MainEventsCleared
RedrawEventsCleared

[filnet]

Can't reproduce on Windows 10.
Seems to affect Windows 7. I'll double check.

[filnet]

I confirm the issue on Windows 7.
I had a hard time reproducing the issue at first. Had to close a bunch of apps.

And found this: https://devblogs.microsoft.com/oldnewthing/20031001-00/?p=42343

But what I am seeing is a CursorMoved every 1 second approximately which the above does not really explain.

[filnet]

Found the cause : http://debugandconquer.blogspot.com/2015/08/the-cause-of-spurious-mouse-move.html

I confirmed that, on Windows 7, having the Task Manager open will trigger those spurious events.
And when the Task Manager is not running, then no spurious events are seen.

So we have to expect spurious WM_MOUSEMOVE messages and handle them.

[filnet]

Found another case: just clicking a mouse button will generate a CursorMoved event even if the mouse pointer was not moved.