The Surface app’s button customization is perhaps what you’d expect from a basic, bare-bones settings app: not all-encompassing, but powerful enough for most tasks. With a Surface Pro 4, you can change the behavior of single click (which by default opens OneNote), double click (screenshot), and press and hold (Cortana), or disable any of the actions entirely. But don’t expect to link buttons to actions or macros: for now, at least, you’re limited to assigning Store apps and programs. (You can program one of the buttons to launch Edge or Word, for example.)
While the configuration options may be limited, they’re far more exhaustive than the functionality offered on the Surface Pro 3 — Microsoft’s deprecated Surface Hub merely let users choose between launching the Store app and desktop version of OneNote. And to that point, initial reports suggest that the Surface Pro 3 pen isn’t compatible with the new Surface app. To get the new button configuration options to appear, you’ll apparently need a Surface 3, Surface Pro 3, Surface Pro 4, or Surface Book paired with the latest generation of Surface stylus.
Pen customization is the largest addition to the new Surface app, but it has gotten minor interface enhancements, too. The User Education setting has been updated with more descriptive titles, and toggle button colors have been updated to conform with Windows 10’s design language. These are all rolling out via the Windows Store in successive waves.