The Windows 8.1 Update that introduces a bunch of interface changes to Windows 8.1 is designed to enhance the experience of mouse and keyboard users, but what about the growing number of happy touch users? About 40 percent (and increasing) of PCs available at retail have a touchscreen (compared to just 4 percent when Windows 8 launched), and for the most part, their buyers enjoy how they work. With touch interfaces a growing part of the Windows ecosystem, Microsoft didn't want to make the touch experience worse.

While many desktop users may want their systems to boot straight to the desktop, this is unlikely to be a popular option for tablet users. Touch laptop users could easily go either way. Microsoft's goal, therefore, was to pick a sensible default based on the kind of system being used.

The way the update does this is based on something called the power platform role, a setting found in the computer's firmware specified by the manufacturer. For Windows PCs, it will typically be "desktop," "mobile," or "slate," for desktops, laptops, and tablets, respectively.

On a slate, the update will continue to boot to the Start screen and continue to use the Metro apps as the default for opening pictures, music, and videos. For anything else, the update should boot to the desktop and use the desktop for those media files. However, this is only true if the defaults haven't been changed; any customizations are meant to be respected.

Another change is the presence (or lack thereof) of the power button on the Start screen. Microsoft told us (and Paul Thurrott) that this was governed by the same power setting. The rationale, which makes sense to us, is that tablet users are generally accustomed to using the hardware power button on their devices (much like smartphone users), and hence don't really need the on-screen button.

However, our own testing leaves us less confident that this is so. Our test Surface Pro, for example, reports itself as a slate but has the power button. There are certainly devices that don't show the button, such as the 8-inch tablets from Lenovo that we looked at recently, so it's clearly not on every device. Our guess is that it may be governed by support for Connected Standby.

If you're not happy with the decisions that the update made for you, you can always change them. Things like app defaults have always been configurable, and booting to the desktop or Start screen could be controlled in the taskbar properties dialog even in Windows 8.1 without the update—the update just changes the default on some systems.

The only setting that is a little weird is the one governing whether the taskbar appears while running Metro apps or not. The toggle for that is in the taskbar properties, but you wouldn't think so to look at it; there's a new option to choose whether Metro apps appear on the taskbar (on by default now on every kind of system). If you disable that latter setting, you'll also disable the taskbar from showing when you bump the mouse at the bottom of the screen inside Metro apps.

Choosing whether or not to have a power button is a little more involved and will require changing registry settings, as outlined here.

The other new UI features are automatic and generally more subtle. For example, the new (and very welcome) title bars that show up in Metro apps? They don't always appear. Start a Metro app with your finger (or tap the taskbar button with your finger), and you won't see the title bar. Do the same with your mouse, and the title bar will appear for a few moments before auto-hiding.

Similarly, some of the hover-activated features are also subtle. Prior to the update, putting the mouse cursor in one of the hot corners immediately displayed a pop-up of some kind: in the top left a thumbnail for app switching and in both right hand corners, the "ghost" charms. With the update installed, the operating system now inserts short delays—just as it already does for the taskbar thumbnails—so that these things don't get in the way if you're just aiming for the application menu or close button.

The Windows 8.1 Update won't make everyone happy. That might change when a future update introduces a kind of Start menu/Start screen hybrid. In the meantime, however, the new UI features may help make Windows 8.1 a little more familiar and a little more comfortable to mouse and keyboard users.