Factorio Forums

So please at least add a description to it (and the LuaStyle) to indicate that it's the progress bar's "thickness" instead.

I only figured it out after looking at the base game's code comments. I spent too long not looking at the base progress bar style because I was trying to make it mimic another element so I could use it's runtime re-colorability and could not figure out why it wasn't displaying the shadow or bottom gradient.

Confusing indeed, description added to the docs for the next version.