I have found that when an Interactive Grid is used in a modal page, scrolling does not work. All that happens is the first 40 rows are displayed, you cannot get beyond these.
I have reproduced this on apex.oracle.com - login as demo/demo. This demo shows the same report (select table_name from user_tables) 3 times:
- As an IG with scrolling on the main page
- As an IG with scrolling on a modal page (press button "Open modal with scrolled IG") - this only shows first 40 rows.
- As an IG with paging on a modal page (press button "Open modal with paged IG")
Is there any way to make this work?