Bernie Wylde wrote:

> In the example, clicking in the window's title bar or grow box 
> produces a _mButDwnEvt but not a _mButUpEvt.
> What's all that about then?

In those cases, the _mButDwnEvt gets forwarded to a tracking routine 
DragWindow or TrackGoAway. These routines take control (i.e. do not 
return) until the mouse button is released, and do not emit an 
_mButUpEvt.

Robert P.