I've written a windowless NPAPI plugin and I want to handle mouse events in NPP\_HandleEvent().

I can get WM\_PAINT, WM\_LBUTTONDOWN, WM\_LBUTTONUP, and WM\_MOUSEMOVE event without any problem.

However, it's wired that I can't receive any WM\_MOUSEWHEEL event.

```
uint16_t CWinLessPlugin::HandleEvent(void *event)
{
    NPEvent *pevent = (NPEvent *) event;

    switch (pevent->event)
    {   
    case WM_PAINT:
         break;
    case WM_MOUSEMOVE:
         HandleIt();
         break;
    case WM_MOUSEWHEEL:
         //never 
         break;
    }
    return 1;
 }

```

I really can't figure out why :(. Any help will be very appreciated.

chrome version : 31.0.1650.63

firefox version : 25.0.1