Much more often than not, when I am using the Diplomacy tab at the top of the screen I plan on talking to all of the other factions in the game one at a time. I find that the current behavior of returning to the main screen after trading with one faction instead of returning to the initial diplomacy screen (where I can choose to talk to another faction) requires more actions on my part. Instead, it should return to the diplomacy screen with the last faction I selected highlighted. This way the game will keep track of my progress through the factions I wish to talk to. This will become more important when more factions are added in future DLCs and when minor races are added (GC2 had lots of minor races, so I assume GC3 will as well).