I recommend studying how the Commodore 64 (multi-colour) char mode works.
A char will only appear multi-colour (wide-pixel) if it's native colour is >7.
But fair enough, you are not the first to have trouble with this idea so I will look into making it simpler for novices.
1. make sure the display mode is "Text - Multi-colour".
2. make sure the "Colour Matrix (low nyb)" colour is one from the bottom row (ie. 8-15), you should see wide red dots on the palette image to indicate WIDE.
You can also find information about all this in the included help files.