Controlling the Align feature in Illustrator.
By default, Illustrator will use your selection's bounding box when aligning or centering objects. Have you ever wished you could tell Illustrator to center everything around a particular object instead?
You can. After you've selected all the objects you want to align, click one object (just click, no shift key). Nothing changes on the screen, but the item you clicked becomes the key object. Illustrator aligns everything else in your selection around that item.
Source: This little-known feature has actually been around since Illustrator 9. It came up while we were preparing materials for a new series of "Making the Move to CS3" classes at Seattle's School of Visual Concepts. Check SVC's class schedule for times in June and July. In addition to covering the new features introduced in Adobe Creative Suite 3, we're adding a special list of 10 cool things everyone missed from the earlier versions too.