The snazzier aspects of the new themes are made possible by new layout options, such as the ability to add gradients to almost any layout object, the ability to change the look of buttons by controlling corner radius precisely for rounded buttons and the ability to highlight buttons differently when users mouse over or press them--behaviors we all expect from well-designed websites. There are many other new design enhancements in FileMaker Pro 12, and one of my favorites is the option "Delineate fields on current record only" in the Layout Setup dialog. You can highlight the selected record in a list simply by putting a check in a box. In the past this required advanced techniques (capturing record ID with a script trigger and using conditional formatting based on a calculation).
Two other changes in layout mode may seem awkward to experienced developers for a while, until old habits give way to new. Layouts in FileMaker Pro 12 now have explicit widths and expect to be used within windows of a certain size. This change is part of FileMaker Pro 12's much better support for different types of displays (desktop computer, iPad, or iPhone, and iPod touch) and is complemented by the new screen-size guides or "stencils" that make it easy for you to tell if a particular layout will fit on a particular screen.
As a longtime FileMaker developer, I found it difficult to adjust to the new way objects are selected in layout mode. In the past, you drew the selection rectangle completely around the object (say, a field, or field label, or button) to select it. In FileMaker Pro 12, objects are selected if the selection rectangle touches any part of the object. The new behavior is consistent with Apple's user interface guidelines--it's how selection works in the OS X Finder, for example. And whether you're an old hand or a tenderfoot, the new behavior certainly makes it more difficult to select one object in a crowded group. Fortunately when you really need it, the old behavior can be recovered by holding down the Command key while selecting.
FileMaker Pro for amateurs
What about the database amateur, the non-developer or the person who just doesn't have a lot of experience creating databases? Too timid to enter layout mode? Not to worry. FileMaker Pro 12 still has lots to offer you, too.