closed account tree view - how do I reopen?

[Phil Groschwitz]

I accidentily closed the account tree view.  The way I did it was by
opening a new window with page, then closing the original gnucash
window.  I was left with just the new window
with page (which was just an invoice) and before I realized what had
happened I clicked save.

Now I can't figure out how to reopen the account tree view!

I'm using version 2.0.1

Help!

Thanks,
Phil