Bernie Wylde wrote: > Any ideas how to make a _kControlGroupBoxCheckBoxProc auto-toggle? > I suspect it needs something like: > bool = _zTrue > def SetButtonData (btn, _kControlCheckboxPart, _kControlAutoToggleTag, > SizeOf(boolean), bool) > but I can't find the right part or tag. Autotoggle is a feature of a control that cannot be set with SetButtonData. There is no "right part or tag". In fact, pre-Panther there was no way to change a control's features. If you are willing to be Panther-only, you can do this: #define HIViewRef as ControlRef // the 2nd & 4th parameters must be 0 toolbox fn HIViewChangeFeatures( HIViewRef inView, UInt32 mustbe0, UInt32 inFeaturesToSet, UInt32 mustAlsoBe0, UInt32 inFeaturesToClear ) = OSStatus _kHIViewAutoToggles = 1 << 14 dim as OSStatus ignore dim as Rect r window 1 SetRect( r, 10, 10, 300, 200 ) appearance button 1,,,,, "Group", @r, _kControlGroupBoxCheckBoxProc long if ( system ( _sysVers ) >= 1030 ) ignore = fn HIViewChangeFeatures( button&( 1 ), 0, _kHIViewAutoToggles, 0, 0 ) end if do HandleEvents until 0 Robert P.