Testing existence of EXTERIOR windows

What's the best way to test whether an EXTERIOR panel exists? I seem to be able to use DoWindow or GetWindow with ordinary panels, but with EXTERIOR panels,
they don't seem to work. Do I need to use names with subwindow syntax, or is there any way using a title?

Thanks.
Yes, you need to use the subwindow syntax. Like so: if(WinType("basewindow#extpanel") == 7) ..