So in 1.12.2 and below, to use the scroll wheel on my mouse to select items, it takes 1 roll/click/thing of scroll wheel to change 1 item. However, in the 1.13 snapshots, it takes 10 or 11 rolls/clicks/things of my scroll wheel to change 1 item. I also tested this using an external program called enjoyable (A program that allows you to set keybinds for Bluetooth and USB buttons, I use it for my Nintendo Switch Joy-Con controllers) and tested scroll clicks for different versions, and it takes one scroll to change items. (edit: IN ALL VERSIONS) I have no idea why this happens, it just bothers me greatly that it does, because it makes items tougher to select when using mouse and keyboard.