I try to recreate the error but i honestly dont know how this could happen.
If i change the GUI size (with CTRL+NUM_PLUS/NUM_MINUS) then i get a scrollbar but its directly beside my mod gui. Yours seem to be at the end of he top bar like the entire GUI_UNIFIER mod wants to scroll for whatever reason. My best gess at this point is that your resolution is to small to show the entire mod gui without overlapping with the chat area.
I've added a toggle button to show/hide additional info which should make the gui a bit shorter.