One of the key selling points to the iPad is its apps. Not only does the App Store offer a huge, huge selection but those apps run very well on the iPad, typically better than on other tablets. Most apps are tailor-made for iOS and since every iPad offers the same 4:3 aspect ratio, the apps should just scale into place regardless of screen size or resolution.This scenario should hold true with the iPad Mini — despite being a smaller tablet with a lower resolution, apps should “just work”. After using the iPad Mini for a week, I have noticed that things aren’t as black and white as they seem. There are, in fact, plenty of apps that are either less functional than they are on “full sized” iPads.Tiny buttons, tiny text fieldsApple’s Human Interface Guidelines call for a 44×44 pixel minimum interactive space for buttons. Unfortunately, not every app developer follows this particular guideline. Actually, not even Apple follows this guideline if you take a look at the purchase app icon in the App Store. On the iPad Mini, smaller buttons are just plan harder to hit. They don’t happen often, but when you find one you’ll know it by how many times you have to tap to get it to recognize your intent.One example of this problem can be found in the HBO Go app. HBO asks that you sign in to your provider in order to grand you access to the extra content offered by the app. The username and password text fields are about half the size of what they should be for the iPad Mini, and as a result it’s easy to either tap the wrong text field or just not open the text box at all. Now, once you are able to sign in, that text box pretty much goes away forever. The search field on the app is more than appropriately sized, and everything is fine.Google+ features menus that slide in from the left through a menu button that is just a few pixels shy of riding the edge of the screen. Due to the thin bezel on the sides of the iPad Mini, Apple has calibrated the sides of the tablet to not recognize you laying your thumb on the screen as a touch intent. This way you can be sure you have a comfortable grip on the tablet when reading. Unfortunately, this also means that you need to press that menu button three or four times in order to make it clear that what you really want to do is tap the screen. This works great on the iPad 4, but is frustrating on the iPad Mini.Less functional appsFor those eager to make the jump to Windows 8, but are unwilling to spend the cash on a new tablet that may or may not do what you want, Splashtop has offered a tool that allows you to remote into a Windows 8 computer and use the touch interface on your iPad to experience Windows 8. On a full sized iPad, this experience it top notch. The guys at Splashtop worked very hard to make sure it legitimately felt like you were using Windows 8 on your iPad, including all of the touch gestures found in Windows 8. While the app says it supports all iPads, the experience on the iPad Mini was less than great.Most of the touch gestures didn’t work, due in no small part to the software not being able to accurate place your finger on the screen when you swipe to access the Start Menu. None of the side-swipe based gestures worked at all. When you switch to mouse input on Splashtop, it became clear that a big part of the problem was that the iPad Mini wasn’t really the size this app was built for. Considering that the Splashtop app is $10 and there’s no way to request a refund through the App Store, I think it is a huge problem that apps be allowed to claim that they work with the iPad Mini when there are clear usability issues.This presents a new challenge for app developers, but the solution could be just as simple as it is in the Google Play Store. If the app isn’t specifically marked as supporting a piece of hardware, it doesn’t show up in the search results.Annoying, but not a crisisThis is something that doesn’t have to be a big deal. If app developers follow Apple’s guidelines and actually test their app on the iPad Mini, this won’t a problem. Apple’s developer tools are well suited for most apps, but not every app fits in that mold. They shouldn’t either, since some of the best apps I have ever used are apps that approach a need from a fresh perspective.As the iPad Mini grows in popularity, apps that are not properly formatted for the tablet are bound to start receiving negative reviews if these small issues aren’t resolved.Found any apps that don’t hold up to your expectations when used with the iPad Mini? Tell us below.