Thank you Borislav Borissov, Naomi Nosonovsky, Steve Gibson:
Sorry, I should have been more explicit. I should not expect anyone to be a mind reader, but it is interesting to know that some exist!
I am trying to have a pair of properties that:

      1.      Shows the modify DateTime of the VCX file
      2.      Shows the Instantiation DateTime of the object

When I set my custom tInstantiated property to =DATETIME(), the class definition evaluates the expression when I close the class designer and it then always shows the same DateTime every time it is subsequently instantiates. The same is true for setting its custom tVcxDateTime property to =FDATE(This.ClassLibrary,1) . One would think to set these properties in the Init method. But rather than having to rely on the subclass to call DODEFAULT() from its Init, I had defined a dummy property with the expression =BaseClass::Init() so that the init at the most ancestral class would auto-fire.

How do I keep this from happening when close the class designer?