如果Delphi TSpeedButton是该组中唯一的一个，它将如何保持按下状态

I'm not sure why the TSpeedButton has this property but when a TSpeedButton is the only button of a given groupindex, it doesn't stay pressed, whether or not "AllowAllUp" is pressed. Maybe a Jedi control would suffice, but hopefully there's some fix. Any help or anecdotes are appreciated.I'm not sure why the TSpeedButton has this prop