func (l *List) PageUp() {
	start := l.start - l.size
	if start < 0 {
		l.start = 0
	} else {
		l.start = start
	}

	cursor := l.start

	if cursor < l.cursor {
		l.cursor = cursor
	}
}
func (l *List) PageUp() {
	start := l.start - l.size
	if start < 0 {
		l.start = 0
	} else {
		l.start = start
	}

	cursor := l.start

	if cursor < l.cursor {
		l.cursor = cursor
	}
}
// PageUp moves the visible list backward by x items. Where x is the size of the
// visible items on the list. The selected item becomes the first visible item.
// If the list is already at the bottom, the selected item becomes the last
// visible item.