class="aligncenter" and class="alignright" ignored on design.canonical.com

[Matthew Paul Thomas]

1. On design.canonical.com, draft a post.
2. Choose "Upload/Insert", select an image, and choose "Center" or "Right" as the position.
3. Preview the post.

What you see: The image is floated left.

What you should see: The image is centered, or floated right with an left margin at least as large as the paragraph spacing.

WordPress applies class="alignleft", class="aligncenter", class="alignright", or "class="alignnone" based on your choice. So the style sheet should have something like:

.alignleft {float:left;margin:0 1em 1em;}
.aligncenter {text-align:center; margin-bottom:1em;}
.alignright {float:right;margin:0 0 1em 1em;}

This is a regression of bug 980875. Perhaps a test needs adding to ensure it does not regress again.