Hi there!

There are a couple challenges to getting underline working correctly in XD, both in terms of its appearance and getting that appearance consistent across platforms. A while ago, Medium posted an article on getting link underlines to look just right, and they explore a bit about what can go right or wrong with underline renditions. For XD, the main things we wanted to get right were:

1. Creating a single underline for adjacent text runs with different styles (for example, font size)
2. Creating gaps around font descenders that would intersect the underline

That in itself wasn't so bad, but unfortunately, as Andrew mentioned, we didn't have this immediately available in our platform, and so we had to build it out. We had to keep it consistent across the editor, canvas, desktop, mobile, and web. And it had to have a consistent round-tripping experience with other formats like SVG.

All of these challenges are surmountable, especially given that we've started building out the feature in development builds. But because the implementation cost was high, we weren't able to sneak it in earlier, and had to wait until there was a bit more breathing room in our schedule. It's been a bit of a mad dash trying to get everything in XD just right, but we're working on it!

Thanks for your continued support of XD, and hopefully you'll see underline soon!

-Bear (Adobe XD Code Monkey)