Class description Choice components render a popup menu or list box with either single or multiple selection.
The multiple slot determines whether multiple elements may be selected at once; if this is set to a true value, then the component value must be a sequence of strings, otherwise it must be a single string.
The size slot determines the number of items visible at one time; if neither this nor multiple is set, the component is rendered as a popup menu rather than a list.
The choices slot determines all possible choices which may be selected. It names a value, rather than storing the choices directly.