Thanks Cathy and Colin for your replies and articles on this topic.

I was drawn into this area due to issues with display of report previews from a top-level application. Spent a lot of time unsuccessfully trying to get legacy In Screen based code to display the preview so that it was visible and not covered by another top-level form.
This too is why I want to minimize the number of forms on the screen at once during the printing process.


>An ExtensionHandler class is just a custom class that MUST have a few specifically named methods
>
>Not in SP1. They're optional from SP1 onwards.