Drupal has pretty good multilingual support out of the box. It's also fairly easy to create new entities and just add translation support through the annotation. These things are well documented elsewhere and a quick search will reveal how to do that. That is not what this post is about. This post is about the UX around selecting which fields are translatable.

On the Content Language page at http://example.com/admin/config/regional/content-language you can select which fields on your nodes, entities and various other translatable elements will be available on non-default language edit pages. The section at the top is the list of types of translatable things. Checking these boxen will reveal the related section. You can then go down to that section and start selecting fields to translate, save the form and they become available. All nice and easy.

I came into the current project late and this is my first exposure to this area of Drupal. We have a few content types and a lot of entities. I was ticking the box for the entity I wanted to add, jumping to the end of the form and saving it. When the form came back though it was not selected. I could not figure out why. It wasn't until a co-worker used the form differently to me that the issue was resolved. Greg ticked the entity, scrolled down the page and found it, ticked some of the checkboxen in the entity itself and then saved the page. The checkbox was still ticked.

The UX on this pretty good once you know how it works. It could be fixed fairly easy with a system message pointing out that your checkbox was not saved because none of the items it exposed were selected.

I feel a patch coming on…