[bug 1858] WM_MOUSEACTIVATE processing

[Ann & Jason Edmeades]

>How about an one line test case which simply does
>ret = DefWindowProc(hwnd, WM_MOUSEACTIVATE, 0, HTNOWHERE);
>ok(ret == MA_ACTIVATE, "expected to return MA_ACTIVATE\n");

Yes, the patch does that (via the window proc for the test, but it gets
forwarded on as its not handled). I didn't think of driving it directly, but
the end result is the same.

I was just concerned in case the default windows procedure does something
different based off windows styles etc. I cant find any evidence it does,
but I'm just paranoid :-)

Jason