chat should let you choose the resource you want to talk to
Right now when somebody from the non-highest-priority resource, a new tab is created associated with that resource. There are two problems with this:
1] Creating a new window for talking to the same person is annoying. It adds clutter that I have to manage and can make the conversation confusing to follow.
2] You are not able to choose which resource you want to talk to. The specific instance where this is useful is if somebody is speaking to you from one resource, but you'd like to a leave a message with a different one for them to get later.
Point 1 is not as important because it seems like there are times when you would want separate tabs for each resource. Specifically if each resource is being used by different people on the same machine or some other similar relationship.
Point 2 is more problematic. You can't initiate a conversation with a specific resource when you need to, they have to start talking with you. It makes the above organization unworkable from a gajim client.