alain_bkr It does show flag of the other party of the "active meeting" as the background of the "Nations" button.
Took me a while to find that one can open that meeting dialog instead of normal nations list by *right* clicking.
Attached patch allows reopening the meeting also from the players dialog. Requires the treaty handling rework present only in S3_2 and later.
3.0 and 3.1
In nation's screen (F3), one can "meet" a nation either by right-click on the name, or "meet" button.
It works when after having met a nation, we accept or reject the treaty
But if instead i press F1, i go back map, then meeting does not work.