[pygtk] prevent gtk.Dialog from closing

[Tasos Latsas]

Hello,
I have a dialog box which prompts the user for some input with an entry
box. I want to be able to check the user input before returning to the
main window and show another popup window with a message,
 e.g. ("you left the field empty, press cancel button or fill it etc")
and then prevent the dialog from closing.

I tried to intercept the delete-event but didn't help also i didn't find
something similar at the faq
Is this possible with a gtk.dialog or i have to use a gtk.window?

thank you in advance