Embed in WordPress cutting off top menu – no scroll

New Vanilla forums on new website. Everything is working nicely except one thread (the lets play and test the forums thread) that once a few comments got on there, the frame shows the bottom, cuts off the top menu and is not scrollable. There is no way to view the top menu on the discussion. Have to use the side nav menus to go to a different thread or discussion to see the menu again.
https://tinypic.com/r/10dz6g6/9

https://www.ads-software.com/plugins/vanilla-forums/