AllowAllUp: Boolean;
The AllowAllUp property determines whether all buttons that are a group, can be in the released state at the same time.
The AllowAllUp property can be used only for the buttons that compose a group (the GroupIndex property of each button has the same non-zero value). If GroupIndex value is 0 (the button does not belong to any group), changing value of the AllowAllUp property does not cause any actions. If the AllowAllUp property is set to False (default), one button of the group should be pressed (value of the Down property is True). When the click is made on this button, its state is not changed (as before it is displayed in "pressed" state). The button is returned to the "released" state, only when the click is made on another button of this group. If the AllowAllUp property is set to True, all buttons can be pressed separately. Change of the value of the AllowAllUp property of one button of the group causes the change of the AllowAllUp value of all other buttons of the group.
See also: