How to make a Delphi TSpeedButton stay pressed if it's the only one in the group

Question

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\

Answer 1

Set AllowAllup to true, and Down to false.

Then in OnClick event:

....
btn.AllowAllUp := not btn.AllowAllUp;
btn.Down       := not btn.Down;
....