When items are stacked on top of each other, you can bring the selected item to the front or send it to the back by pressing a keystroke:
F5: Bring to Front
Shift-F5: Send to Back
Add the Option or Alt key to bring forward one level or send backward one level:
Option/Alt-F5: Bring Forward
Option/Alt-Shift-F5: Send Backward
OR, just right-click or Control-click on an item to bring up the contextual menu and choose one of the options under Send & Bring:
Jay Nelson is the editorial director of PlanetQuark.com, and the editor and publisher of Design Tools Monthly. He’s also the author of the QuarkXPress 8 and QuarkXPress 7 training titles at Lynda.com, as well as the training videos Quark includes in the box with QuarkXPress 7 . In addition, Jay writes regularly for Macworld and Photoshop User magazines and speaks at industry events.