All users who have editing(modify) permissions can have editing versions. To know whether or whom of the other users have a working version, it is now possible to display another collumn in the Structure list , in which the number of  editing versions is specified. If you click on it, you will receive a detailed view.

In this example, you click on "2" which is in the collumn "edit versions" and you receive the following information:

One can easily understand which users have editing versions.