Can I view the preview in a different browser tab or window?

Yes, there's actually a trick that lets you do this: if you open the same project in two different browser windows, hide the preview in one, and hide the source in the other, the preview in the second window will still update as you make edits.

To hide the editor or preview panes, simply click on the arrow buttons at the top of the vertical divider bar (located between the writing pane and the preview pane).