Fix editing of coordinate system in fields using 'gfx define field' for case where only the coordinate system is being changed.  https://tracker.physiomeproject.org/show_bug.cgi?id=3774
Fix editing of coordinate system in fields using 'gfx define field' for case where only the coordinate system is being changed.  https://tracker.physiomeproject.org/show_bug.cgi?id=3774

cmiss/cmgui,cmiss/cmgui