We released an improvement in the User Experience of working with locales where we now allow the display of only 1 locale (which is no the default one). This is useful for entries that have a lot of fields, making the editing of its fields across many locales hard.

This feature can be enabled by selecting "Single locale" in the sidebar widget:

It also comes with some error reporting capabilities so that it's easier to pinpoint which locales have how many errors.