🚀 go-pugleaf

I would like to imitate an interesting property of the Clock applet in Windows
3.1 (I don't remember now if the one in 3.0 did this). When you select the "No
Title" setting, holding the left mouse button down in the clock window puts it
into the move mode the same as in the caption of of a normal window. How does 
it do that? Is there an easy way (some undocumented windows fuction) or do they
do it "the hard way" (LbuttonDown, SetCapture, GetDC, MouseMove, etc.) Is it 
significant that it only does this when there is no title bar?

Thanks

Steve Marshall