Stepper

ui.Stepper creates a pair of arrows changing a *float64 by a step between two bounds, as AppKit's stepper beside a field: a click on an arrow steps up or down, as do Up and Down while the stepper has the keyboard focus, and holding an arrow keeps stepping, faster the longer it is held. Changed reports a new value.

ui.Row(c).Gap(6).Children(func() {
	ui.Textf(c, "%.0f copies", app.copies)
	ui.Stepper(c, &app.copies, 1, 99, 1).Label("Copies")
})

For a number the user also types, use a number input, which has steppers of its own.

Accessibility

Assistive technology sees a spin button of the value, named by its Label, which it increments and decrements.