closing 1 of 2 windows

Could perhaps be tweaked, but one idea is:

Strict

Local Window:TGadget = CreateWindow( "Window", 10,10, 400,200)
Local sWindow:TGadget = CreateWindow( "sWindow", 10,300, 400,200)

Repeat
	PollEvent
	If EventID() = EVENT_WINDOWCLOSE Then
		If EventSource() = Window Then
			FreeGadget Window
			Window = Null
		EndIf
		If EventSource() = sWindow Then
			FreeGadget sWindow
			sWindow = Null
		EndIf
		If (Window=Null) And (sWindow=Null) Then End
	EndIf
Forever