Suggestion

[gleaming sigil]

You guys should add native support for locked inventory slots with customizable items that execute commands on click.

[scenic pasture]

What plugin

[runic knot]

deluxemenus is a menu plugin meant only for menus, not to control items in your inventory

few names I know are commanditems itemcommands and joinitems
multiple plugins of each name I think ngl

I think joinitems might be the one where it can lock an item in your hotbar