Windows 8 introduced a new programming model for Windows apps, based on the Windows Runtime (WinRT), which lets users dynamically change the size of screen elements with a PC setting. You can see what this option looks like in the PC settings in Figure 1. On my desktop, the options are Default and Larger. On my Surface Pro, the options are Smaller and Default. It really depends on the device, and in particular, the vertical resolution of the attached displays. More important, Windows Store apps receive an event whenever this option is changed and can thus dynamically update their rendering code to reflect the current scaling factor.