Does anybody know of an efficient way to add an additional tag to a task using the keyboard?

For example, I have a task with the tag "waiting", later on I want to add the tag "joe", so that the task ends up having "waiting" and "joe" as tags. However, the only way I can add the second tag from the keyboard is by hitting the arrrow key. I would hope to have used the tab key instead (it seems more natural).