We all know that if you hold your mouse on an item in a GUI and press a number on your keyboard (for example 1), it'll go to that slot in your hotbar... You can also use thes numbers to quickly navigate through your hotbar when in-game (not in GUI)
For that last option you can change the button you want it to be for that slot in your hotbar to whatever you want in your controls (For example: I prefer my 9 slot in hotbar on button 3, that's the scroll button on your mouse)
But I can't hotkey items to my 9th slot with my scroll button as done in GUI when using the normal numbers (1-9)
Can this (bug) be fixed... it kind of bothers me