Display on Primary, Secondary, Current Monitor

Hi,
I tested the settings of Primary, Secondary, Current Monitor. But even if I try to use the setting "current" my session open on the Secondary Monitor. How that setting work? I thought the meaning of "current" is that the session open on the same Monitor as the RDM Console is located.
My problem is as follow: We are a Group of user working on the same sql database. All user have 2 monitors. Some have on the primary monitor a higher resolution than on the secondary monitor. Therefore work the setting "smart sizing" if they move to the other monitor and resize to that max. resolution. But we have also user they have on the primary monitor a less resolution than on the secondary monitor. If they move to the other monitor (higher resolution) the session has to resize to that max. How can I realize that?