Hello, Please use below solution. Form-> OnCreate procedure TMainmForm.UnimFormCreate(Sender: TObject); begin with UnimSegmentedButton1, JSInterface do JSAddListener('painted', JSFunction('a', 'a.getPressedButtons()[0].innerElement.dom.style.backgroundColor= "#00AA00";')); end; UnimSegmentedButton -> ClientEvents -> ExtEvents -> toggle function toggle(sender, button, isPressed, eOpts) { if (isPressed){ button.innerElement.dom.style.backgroundColor= '#00AA