QuarkXPress 10 is enabled with the modified Space/Align feature, which was not available in previous version. The Key Item Space/Align feature lets you align and space objects relative to a key item in the layout; just select a key item first, and everything else will be relative to it. You need to select the first item and no matter how do you select the rest of the objects.
For more information please go to the link below:
http://www.quark.com/Products/QuarkXPress/Features/Powerful_Design_Tools.aspx#8