Over a year later, I have this exact issue. Did you ever find the cause or solution?
Additionally when I right click on the Calendar icon in the navigation pane and select open in new window nothing happens. I have a hunch they are related issues.
OS is XP Pro, running Outlook 2010 via Microsoft Exchange. The "Find A Contact" search box appears but won't let me type anything into it. If I click on the box "Find A Contact" quickly disappears then reappears which prevents me from actually typing anything into the box.
Help!!!
Thanks!

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