Highlight a object behind a transparent object?

if it is behind the wall it looks like that, but looks like a normal part when not behind it, is it possible to do without scripting?

Put the depthmode to alwaysontop.

You can’t do that at the moment with the current Roblox’s Engine, on top of that Highlights are extremely buggy and glitch out at some point.
I do not suggest using highlights for ingame decorations and more focused on highlighting players and such.

But there’s always some sort of way to do an alternative method to it. There was once a discussion about this to a similar meaning.

You’re right, but I’ve seen people work with highlight using scripts and so this can be an exception for some people, but you’re not wrong either.