>i want to execute a procedure whenever a button's enabled status change.
>how to do it ?

The simplest way will be to use Enabled_Assing method to fire a procedure. Select this property in the Property Sheet and fire a PEM Editor and activate Assign method for this property.

Actually, I take it back. It only works for the form itself. For the button to work it has to be of a special class which have this method implemented there.