Organizing currently open files in folders / groups

It would be nice if you could organize the currently open files in folders or group them together in the upper bar.

Sometimes I need to work on several projects, i.e. to get some source code from one project to include in another.

This feature would help you to stay organized and have an overview over all of the projects you are working on.

The feature could look something like this:

Maybe this feature could also be included into the side bar: