Steps to reproduce. In wikitext editor 2016. On this site, I click after edding some images (see revision) on Save changes, pop up window comes, I click See changes, I click Save changes, pup up window comes, but inmediatelly disapper, because page is safed. This is unexpected behaviour as normally you can see preview and than you can also add edit summary.
Experienced on cs an pl Wikipedia. FF 51.0.1