There’s a back button in the Formatting toolbar (why Formatting? Because…um…look at that interesting thing over there!). I.e., Window->Toolbar->Formatting.
Thanks John,
I don’t think I would have looked there!
In case any one else is reading this. The back button is not there by default. You have to right-click on the “help” button on the right, and then select customize toolbar. You will see a back-button that you can drag to the toolbar. (This is 10.2, MacOs).