Directory page

Hello.

On the directory page, after a user clicks the next button, I want to check the selected directory against some criteria, just before leaving the page. I do not want the user to leave the page until the criteria are met. How do I achieve this? I am using MUI_PAGE_DIRECTORY

either, use MUI_PAGE_CUSTOMFUNCTION_LEAVE before MUI_PAGE_DIRECTORY... or see details about the callback funtion .onVerifyInstDir