Use key/button functions for menu

menu.go

@@ -72,6 +72,7 @@ func (this *Menu) TearOff () {
 	this.torn = true
 
 	window, err := this.parent.NewChild(this.bounds)
+	window.SetIcon(tomo.IconListChoose)
 	if err != nil { return }
 
 	visible := this.Window.Visible()
@@ -91,20 +92,20 @@ func (this *Menu) newTearLine () tomo.Object {
 	tearLine.SetRole(tomo.R("objects", "TearLine"))
 	tearLine.SetFocusable(true)
 	tearLine.OnKeyDown(func (key input.Key, numberPad bool) bool {
-		if key != input.KeyEnter && key != input.Key(' ') { return false }
+		if !isClickingKey(key) { return false }
 		return true
 	})
 	tearLine.OnKeyUp(func (key input.Key, numberPad bool) bool {
-		if key != input.KeyEnter && key != input.Key(' ') { return false }
+		if !isClickingKey(key) { return false }
 		this.TearOff()
 		return true
 	})
 	tearLine.OnButtonDown(func (button input.Button) bool {
-		if button != input.ButtonLeft { return false }
+		if !isClickingButton(button) { return false }
 		return true
 	})
 	tearLine.OnButtonUp(func (button input.Button) bool {
-		if button != input.ButtonLeft { return false }
+		if !isClickingButton(button) { return false }
 		if tearLine.Window().MousePosition().In(tearLine.Bounds()) {
 			this.TearOff()
 		}