With mods like Quark and maybe other inventory sorting mods, opening the GUI looks like this https://prnt.sc/tvyu3l .. increasing the space between the players inventory and the backpack inventory might solve these issues..

the buttons in question ( those in my screenshot ) are the ones that sort the players inventory and those on top, next to the inventory name are the ones that sorts the chest/backpack inventory.

Hm, i guess i forgot about this one... its come up before, and i thought i had done it already... lol

Duplicate of #15 Hopefully going to work on this this weekend.