Hide glyph preview?

I’m working on a layered color font using the CPAL method. Some glyphs don’t have any paths for some colours and I can see the default glyph preview that is used for empty glyphs when I preview the font (see below). Is there a way to disable this preview so it isn’t visible?


Can you send me the file for testing?

Here’s a sample file. I don’t think it’s a bug though, more likely user error or it isn’t possible.

TEST.zip (2.0 KB)