[jvorzimmer]

Originally Posted by kovidgoyal

They are already visible, as jackie_W pointed out. @lomkiri you can enter unicode chars using hex codes already, see https://manual.calibre-ebook.com/edi...ial-characters

But, Kovid, that only shows non-breaking spaces and hyphens. I would like some indication of zero-width non-breaking spaces in the editor without having to go to the code view.