Closing one Outlook window closes the application

[Rob W.]

A few days ago, I opened Outlook 2007's Contacts folder in a new window. Now,
everytime I start Outlook both windows open (Inbox and Contacts). That would
be fine except for this: everytime I close *only* the Contacts window, the
Outlook program itself closes (Contacts, Inbox window and all).

Thanks for your help!

Rob W.