Depending how complex your need is, you can simulate Enabling with a logical form property. I assume you don't want the Click to fire? In the top of your Click:

IF ThisForm.lDisabled
RETURN
ENDIF

The button is never actually disabled, so wherever you were going to disable it, you need to gray the text to make it look disabled (I think the default is ForeColor(128,128,128) and set the property.