diff --git a/callbacks_unix.go b/callbacks_unix.go
index 717150c..e627583 100644
--- a/callbacks_unix.go
+++ b/callbacks_unix.go
@@ -27,9 +27,7 @@ import "C"
 func our_window_delete_event_callback(widget *C.GtkWidget, event *C.GdkEvent, what C.gpointer) C.gboolean {
 	// called when the user tries to close the window
 	s := (*sysData)(unsafe.Pointer(what))
-	b := false		// TODO
-	s.close(&b)
-	return togbool(!b)		// ! because TRUE means don't close
+	return togbool(s.close())		// ! because TRUE means don't close
 }
 
 var window_delete_event_callback = C.GCallback(C.our_window_delete_event_callback)
diff --git a/delegate_darwin.go b/delegate_darwin.go
index 27031c3..b1daece 100644
--- a/delegate_darwin.go
+++ b/delegate_darwin.go
@@ -26,9 +26,7 @@ func makeAppDelegate() {
 //export appDelegate_windowShouldClose
 func appDelegate_windowShouldClose(win C.id) C.BOOL {
 	sysData := getSysData(win)
-	b := false		// TODO
-	sysData.close(&b)
-	return toBOOL(b)
+	return toBOOL(sysData.close())
 }
 
 //export appDelegate_windowDidResize
diff --git a/stdwndclass_windows.go b/stdwndclass_windows.go
index ac5dfd9..f6dd395 100644
--- a/stdwndclass_windows.go
+++ b/stdwndclass_windows.go
@@ -164,9 +164,8 @@ func stdWndProc(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam _LPARAM) _LRESUL
 		}
 		return 0
 	case _WM_CLOSE:
-		close := false		// TODO decide apt default
-		s.close(&close)
-		if close {
+		if s.close() {
+			// TODO destroy
 			s.hide()
 		}
 		return 0
diff --git a/sysdata.go b/sysdata.go
index 9144517..9ff6ee9 100644
--- a/sysdata.go
+++ b/sysdata.go
@@ -10,7 +10,7 @@ type cSysData struct {
 	alternate bool        // editable for Combobox, multi-select for listbox, password for lineedit
 	handler   AreaHandler // for Areas; TODO rename to areahandler
 	winhandler	WindowHandler	// for Windows
-	close	func(*bool)	// provided by each Window
+	close	func() bool	// provided by each Window
 	event	func()		// provided by each control
 }
 
diff --git a/test/kbtest.go b/test/kbtest.go
index 4e97708..9945772 100644
--- a/test/kbtest.go
+++ b/test/kbtest.go
@@ -75,9 +75,6 @@ func (a *keyboardArea) Key(e KeyEvent) (repaint bool) {
 
 type kbhandler struct{}
 func (kbhandler) Event(e Event, d interface{}) {
-	if e == Closing {
-		*(d.(*bool)) = true
-	}
 }
 
 var doKeyboard = flag.Bool("kb", false, "run keyboard test (overrides -areabounds)")
@@ -85,6 +82,7 @@ func kbTest() {
 	wid, ht, ah := mkkbArea()
 	a := NewArea(wid, ht, ah)
 	w := NewWindow("Hi", wid, ht, kbhandler{})
+	w.Closing = func() bool { return true }
 	w.Open(a)
 }
 
diff --git a/test/main.go b/test/main.go
index db01d15..52ce152 100644
--- a/test/main.go
+++ b/test/main.go
@@ -18,6 +18,12 @@ import (
 type nullwinhandler struct{}
 func (nullwinhandler) Event(Event, interface{}) {}
 
+func die() bool {
+	// TODO we want the bool return to happen before the Stop...
+	Stop <- struct{}{}
+	return true
+}
+
 var prefsizetest = flag.Bool("prefsize", false, "")
 func listboxPreferredSizeTest() *Window {
 	lb := NewListbox("xxxxx", "y", "zzz")
@@ -242,6 +248,7 @@ func areaTest() {
 		modaltest:	modaltest,
 		repainttest:	repainttest,
 	})
+	w.Closing = die
 	w.Open(layout)
 	go func() {
 		for t := range timechan {
@@ -264,9 +271,6 @@ type areatestwinhandler struct {
 }
 func (a *areatestwinhandler) Event(e Event, d interface{}) {
 	switch e {
-	case Closing:
-		*(d.(*bool)) = true
-		Stop <- struct{}{}
 	case Clicked:
 		switch d {
 		case a.resize:
@@ -311,6 +315,7 @@ func areaboundsTest() {
 	w := NewWindow("Area Bounds Test", 320, 240, &areatestwinhandler{
 		a:	a,
 	})
+	w.Closing = die
 	w.Open(a)
 }
 
@@ -367,6 +372,10 @@ type testwinhandler struct {
 func runMainTest() {
 	handler := new(testwinhandler)
 	handler.w = NewWindow("Main Window", 320, 240, handler)
+	handler.w.Closing = func() bool {
+		println("window closed event received")
+		return die()
+	}
 	handler.b = NewButton("Click Me")
 	handler.b2 = NewButton("Or Me")
 	handler.bmsg = NewButton("Or Even Me!")
@@ -481,9 +490,6 @@ func runMainTest() {
 
 func (handler *testwinhandler) Event(e Event, d interface{}) {
 	switch e {
-	case Closing:
-		println("window closed event received")
-		Stop <- struct{}{}
 	case Clicked:
 		switch d {
 		case handler.b:
diff --git a/window.go b/window.go
index 57283f2..e485723 100644
--- a/window.go
+++ b/window.go
@@ -8,6 +8,13 @@ import (
 
 // Window represents an on-screen window.
 type Window struct {
+	// Closing is called when the Close button is pressed by the user, or when the application needs to be quit (should the underlying system provide a concept of application distinct from window).
+	// Return true to allow the window to be closed; false otherwise.
+	// You cannot change this field after the Window has been created.
+	// [TODO close vs. hide]
+	// TODO nil
+	Closing		func() bool
+
 	created    bool
 	sysData    *sysData
 	initTitle  string
@@ -103,9 +110,7 @@ func (w *Window) create(control Control, show bool) {
 		}
 		w.sysData.spaced = w.spaced
 		w.sysData.winhandler = w.handler
-		w.sysData.close = func(b *bool) {
-			w.sysData.winhandler.Event(Closing, b)
-		}
+		w.sysData.close = w.Closing
 		err := w.sysData.make(nil)
 		if err != nil {
 			panic(fmt.Errorf("error opening window: %v", err))