A check item is displayed as a visual indicator, such as a box, that appears checked (representing On) or unchecked (representing Off) to indicate its current state. Selecting a check item at runtime toggles it to its opposite state.
A radio item is displayed as a visual indicator, such as a circle, that appears filled (representing On) or unfilled (representing Off) to indicate its current state. Selecting an unselected radio item in the group deselects the currently-selected item. A radio item must belong to a menu radio group of two or more related items, of which one and only one always must be On. Items of the same group must be displayed contiguously on the same menu.