Comment 1 for bug 1520819

Yes, that is a problem on smaller screens, e.g. some laptops.
I suggested a patch for this upstream [1], that puts the parts of the account configuration dialog into the tabs of a Gtk.Notebook.

Here is how this looks like: http://snag.gy/pCHvK.jpg

The patch is not reviewed so far.

If this would be a solution for elementary os, I could do according adjustments to data/ui/login.glade and provide a patch for pantheon-mail / mail (as it differs slightly from the version upstream).
[1] https://bugzilla.gnome.org/show_bug.cgi?id=714104