Problem:

In Character Dialog there is a procedure P000. In global dialog this is called the first time a character screenset is called and in local dialog it is called when a panel is first entered.

What is the equivalent of this is Graphical Dialog System.

Resolution:

In GUI Dialog there is a SCREENSET-INITIALIZED event in global dialog.

This is executed when the screenset is run for the first time. Its only called first time and will not execute on re-entry to the screenset following a RETC etc.

On specific windows you could also use the WINDOW-CREATED event as an equivalent for P000.