I am using jQuery UI 1.10.3, and jQuery 1.9.0 version.

 

I have both jQuery datepicker and sharepoint people picker in a page. when i click the datepicker icon, the sharepoint 2010 people picker gets hidden. Try without sharepoint 2010 ribbon. This is happening only in IE7, It works fine in IE8.

 

About people picker rendering:

Not able to find how datepicker affects div in people picker. In People picker, the div which is showing the value gets hidden. The div is contained in a table. The div will have span elements as values.