Picture worth a thousand word; GUI shows scroll box when some other mods are installed, thought maybe it is on your end cause multiple mods cause this: orbital ion cannon and bob's rpg and avatar switcher verified to cause this issue. https://imgur.com/a/BOIrhjk
P.S. sorry didn't catch myself in time and submitted before selecting correct catagory: bug.
This was done to be the elements of the gui were in the same place and not shifted when flipping tabs and pages with items. Now i need to think about how to do it right ...
