Force Page1 redraw on Dialog close

As per subject heading.
Without using a timer on Page1 to check for a changed variable,
how do we force Page1 to refresh after a Dialog close ?

I don't want to hide Page1 on Dialog launch as the dialog is
designed to appear within Page1...

Onclose (page.redraw) - On dialog
Onshow(page.redraw) - On page1

These don't appear to help in this scenario.

I understand why, but is there a way around this ?