There's some discussion of a similar report at https://issues.civicrm.org/jira/browse/CRM-16251
. (The items were reported by the same person and seem likely to have a causal relation -- ie 16251 causes 16281.) You'll find some theories and questions on that issue.
The main problem right now is that I've been unable to reproduce the problems. Fundamentally, I need steps to follow that will produce the same problem on a clean site - or I need full access to a test environment which exhibits the problem. If anyone can provide that, it would be greatly appreciated.
FWIW, the screenshots you've posted seem to show a Joomla site. This is interesting because there have been a handful of other unreproducible problem reports. To my recollection, the unresolved ones have either involved screenshots from Joomla -- or have been unclear about CMS. This isn't a strong proof of anything (could be coincidence), but it would be interesting if we could confirm/deny that there's a Joomla correlation. (Note: I have tested some of these reports in a vanilla Joomla site, and it's works fine for me, but there could be some common add-ons or configurations which conflict.)
Final note: in a crunch, you can re-enable the old UI by adding this to civicrm.settings.php:
AFAIK, we haven't done anything to specifically break the old UI (although it's not tested and is scheduled for removal in 4.7). This might serve as a temporary work-around if you're suffering a major regression. However, it's still important to report problems (along with steps to reproduce) so that the main mailing UI can get fixes.