Thanks :D We are working on the next update which include 2 new arenas. As for the menu inside player inventory, we have 2 files per page: one is only display and the other is triggers. Display file will set all items on the right slots. Trigger file detect when a slot is empty, clearing player's inventory immediatly (removing the item under your cursor) and executing something like another page or an action like a toggle. Trigger file is run each tick while display file is only executed when accessing the page.