Arabic RTL fonts do not reneder

[iq0099]

When writing Arabic font, the editor writes the words correctly, however, once you click outside, the words break up into boxed X's.

However, when scrolling through the fonts I was able to find some fonts that render the words correctly.

### Writing

### Rendered

[Keavon]

This is because we currently do not have a fallback sequence. In other applications, missing characters are replaced (without you noticing) with a different font in the fallback sequence that has the character. In Graphite, you currently have to pick a supported font for the character set you intend to use.