When drafting an email it is frequently the case that you need to reference information in one or more other emails. There are presently two ways to do this. First save a draft, reference the information in the other e-mail and return to your draft. The other method is to open Gmail in another tab and switch back and forth between tabs.

A more convenient way of doing this would be allow the user to have another view of their inbox below the message they are composing. This would be exactly the same as the view of your inbox that you get when you click Create a filter.

Extending this idea, it would be even better to be able to simultaneously reference *multiple* emails on the the same page. Thus, when in compose mode, you can imagine having a "New inbox view" button right next to the Send Save now and discard buttons.

If you are a Gmail user please voice your support in this thread!

If you are a Googler reading this thread, please forward this great idea along to one of your best friends on the G-mail team. They could even add it as a G-mail Labs feature =)

You can actually do a "new window" on an individual email to have separate emails opened at once. It opens the whole thread. I usually find that this is sufficient for the use case you're describing.

That suggestion is equivalent to one of the first two scenarios I described, except that you have to change windows instead of tabs. I'd prefer to stay within the same scope at all times.