app/internal/wm: [macOS] close display link after window close

The app.Window owner may run SetAnimating just before window close,
which in turn rely on an active display link. This change makes sure
the link is stopped after window close where no more driver calls
can occur.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/internal/wm/os_macos.go

@@ -344,10 +344,11 @@ func configFor(scale float32) unit.Metric {
 //export gio_onClose
 func gio_onClose(view C.CFTypeRef) {
 	w := mustView(view)
-	w.displayLink.Close()
 	w.w.Event(ViewEvent{})
 	deleteView(view)
 	w.w.Event(system.DestroyEvent{})
+	w.displayLink.Close()
+	w.displayLink = nil
 	C.CFRelease(w.view)
 	w.view = 0
 	C.CFRelease(w.window)