func main() { var mw *walk.MainWindow var windowIcon *walk.Icon counter := 0 if _, err := (MainWindow{ AssignTo: &mw, Title: "Walk Image Icon Example", Layout: HBox{}, Children: []Widget{ HSpacer{}, PushButton{ Text: "Push me", OnClicked: func() { ic, err := walk.NewIconFromImage(makeDigitImage(counter)) if err != nil { return } counter++ mw.SetIcon(ic) if windowIcon != nil { windowIcon.Dispose() } windowIcon = ic }, }, HSpacer{}, }, }.Run()); err != nil { log.Fatal(err) } }