Okay, I see the problem now. It’s because you’re saving it as a .lua file. In Lua there’s no such thing as LocalScripts and Scripts – those are classes ROBLOX created. Make sure when you save to set the file type to .rbxm or .rbxmx:
Sadly it defaults to .lua and there’s no way to change that (to my knowledge), so you’ll have to manually change the file type every time you save just a script.