If I set the initial display to 640x480, then resize, the mouse will only be trackable in the first 640x480 region. I tested this by setting the initial display to 1280x800, then my mouse limits expanded.

Thanks

I can confirm this in Wine. It works fine under Linux though so the problem must be in the Windows mouse driver. I filed a bug report: https://sourceforge.net/tracker/?func=detail&aid=2947403&group_id=5665&atid=105665

It's fixed in SVN now.

The fix doesn't seem right. I haven't investigated it fully, but:

In the WM_ACTIVATE case we call d->vt->switch_in(d), which leads to wgl_switch_in, which calls al_set_mouse_range(), which calls new_mouse_driver->set_mouse_range(), which calls wmouse.c:set_mouse_range which calls al_get_current_display(). But of course we're still in the middle of handling WM_ACTIVATE.

Also, why would wgl_switch_in need to call al_set_mouse_range but not d3d_switch_in?

EDIT: PS. I am delaying 4.9.17 for this.

I think that set_mouse_range call is a remnant of the old directinput mouse driver. It doesn't seem to be needed so I commented it out.