I want to enable/disable a command button depending on a combination of selections of various controls: a few groups of radio buttons, a number of checkboxes and others.

The cumbersome inelegant way is to check the state of all those controls whenever any of them is changed. A very convenient way to deal with this when it's a variable that must change its value, is to make it into a form property that tests the control state in its Let procedure. Is there a similar approach for a control's property?