I just created a PR to incorporate the addon "Easy Compose" that had been created by @Jools into the core:
github.com/friendica/friendica…

There are some optical changes, mainly the button design and their position (they are now created via the template not by JS) and the preview is automated. Everything else is kept mainly unchanged.

I think that @Jools did a great job there. That's why I wanted to have it in the core. Please have got a look at it, once the PR is accepted.