>Have come across an ancient application whereby none of the base classes were subclassed.
>
>I remember reading somewhere of a technique whereby you could effectively subclass the original 'textbox', 'listbox', etc, classes without replacing them in the forms.
>
>Could anyone advise please?
>
>TIA
>
>Dennis

I haven't read anything, but I suppose you could open the metafiles:

use MyForm.scx

and then do some REPLACE:

replace class with "cTextBox", classloc with "MyDerivedClasses.vcx";
  for lower(class) = "textbox"

Repeat for other base classes. Repeat in a loop for all forms and form classes.

CAUTION: Make backup first. Replacing metadata can lead to unexpected results sometimes.

HTH, Hilmar.