As a Roblox developer , the behavior of the lock button is unsatisfying. Unlike its neighbor functions, there is no way to affect the locked property of the selection.
When you click on the button above Lock, Group, it will group all selected parts in a model and put it in Workspace.
When you click on the button below Lock, Anchor, it will toggle the anchor property of all selected parts and descendant parts.
When you click on the Lock button, nothing happens. The only options available are Lock tool and Unlock all, neither of which provide the ability to lock and unlock selected parts.
Expected behavior: when you click on the Lock button, it will toggle the locked property of all selected parts and descendant parts. This will provide a unified experience across all three buttons.