12. Font Substitution
When text is displayed on the web or by a modern text editor, font substitution will be used. This means that any parts of the text for which the primary font lacks glyphs, another font will be substituted. This is highly undesirable for text art as it results in a misaligned textual grid due to the usage of different fixed-width fonts.
For the above reason, Monodraw does not use font substitution and will display a question mark with a red background to indicate that a particular character is unsupported in the current font.
If you want to check whether your diagram would render correctly, change the font from the Preferences and inspect the canvas for any unsupported characters (question marks with red background).