Do anybody knows why on my laptop the fn+f3+B not working? it's important to see hitboxes in speedrun Do bind this to other button is banned?

You're using the incorrect hotkey. To enable hitboxes; use F3+B (without FN). remapping keys is allowed.

@midgh its like that if your playing on some laptops I used to play on one before and using a normal keyboard should work scince thats what I did 3 years ago