I presume you mean scrolling by the mouse wheel and not form scroll bars? There are ways to disable the mouse wheel, and based on your post, I suspect you'd need to turn this on/off by calling the code from the sub form and main form. Not sure if you'd need the activate, focus, or current event for the forms. Here's a site that purports to have a faster, more reliable way to do this. Note: I have no affiliation with the site.
http://www.everythingaccess.com/tuto...n-Access-forms
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.