At the moment if you put a block in the 'Highlighted' region it floats to the left, since it's a 100% region.
We have the status messages and help text block there and we have put a special class in their templates so the content of these is center-aligned. This is not sustainable as we can't expect users to create a template file per block in this region.
The region looks great after #3044250: Make the highlighted region more presentable, but has now thrown up this issue.
Let's figure it out.
