checking more than one item in c check-component of a menu

I want a user to be able to check more than one item at a time in a
check-component of a menu. Is there a way to do this? The default behavior
is that the menu closes and must be clicked on again to check another item.

An alternative which would be OK is to have a way to activate a menu under
program control, so that when the user clicks a
check-component item, the callback reactivates the menu.

Thanks for any help.

Jim Bushnell
jcbushnell2@comcast.net