Use Appropriate Native Form Controls

It almost never makes sense to use non-standard widgets and form controls. In case of native applications, not only is it more confusing to the user to see widgets that are not part of the UI toolkit of the native platform, it also contributes to a feeling of "this program was not written for my platform". Applications such as iTunes for Windows choose to reimplement Mac-style widgets, blatantly disregarding Windows Human Interface Guidelines.

The most common reason (excuse, perhaps?) used by applications developers when choosing to use non-standard widgets is branding. They want to make their application look like none other. You see the problem right there, don't you? When an application looks like none other, it stands out like a sore thumb.

Standards are set for a reason. Branding can be achieved by several means, many of which do not impact usability negatively.

Even when using standard widgets, make sure your usage of it aligns with the purpose it was designed for. Otherwise we end up with widgets like this, where a simple checkbox would have been the logical choice for a yes/no answer, not a pair of radio buttons. This screenshot is from the Security Preferences of Facebook.com. It lets you pick which of several notifications to send you. There are exactly two options in each of several sets of notifications, but each uses a pair of radio buttons instead of a single checkbox.

Car dashboard switches: And now for something completely different.

I had rented a Dodge minivan for the weekend, and took a few minutes to get acclimatized to the unfamiliar arrangement of buttons and switches and toggles and levers on the steering wheel column. I was testing out what I thought was the dimmer control for the dashboard lights — move it up and the speedometer and odometer backlights would glow brighter; turn it down, and they would glow dimmer.

But while I was doing that, my cousin seated behind me pointed to the lights in the passenger compartment, and wondered aloud why they were turning on and off alternately. I hadn't even noticed because these lights are located behind the driver.

It turns out that on the speedometer backlight dial, if you go past the highest point on the scale, it switches on the lights in the passenger compartment. I have no idea why.

In the photo above, I'm referring to the tiny up-down regulator control, to the right of the giant knob.

What good reason is there to map two such dissimilar functions onto the same physical control? There aren't even two different modes of operation; just that an arbitrary position on the up-down dial is mapped to an entirely unrelated function.