WPML compatibility – backend user selected language does not work.

When I activate WPMU dashboard the user selected language in the backend does not work anymore. To clarify. I build a site for French customers, but to make it easy for myself I can set the backend language to EN, so I don’t need to know all options in French.

This works fine, but as soon as I enable WPMU dashboard, the backend switches to FR (default for site) and can not be changed.