I remember vaguely from a previous job that it was possible to have the following setup (I could be wrong):
Note that there is only one page in question. Both boards are visible on the same page, and you are able to drag an issue from one "board" to the other.
One section of the page shows a Kanban board with some collection of columns. Another section of the page (below the first section) shows a Scrum board with some other collection of columns. The result is that developers are able to view the status of issues that are not part of a sprint. In other words, you can do work on issues that are not at all related to any sprint, and see the status of those issues independently of the current sprint. For example, you might have a big backlog, and some of the issues in the backlog are not selected for the sprint, but those issues can still be worked on and have a status.
I remember being able to work on an issue that is not part of the current sprint, and still see the progress of that issue on the same screen as the sprint overview (in a separate collection of columns) on the same screen/page.
Is this a classic thing, or is it still possible? Am I wrong in saying that this was ever possible?