After using the iPad for several days, its limitations are becoming more clear. Here are five things about the iPad that are completely annoying.1. Lack of Compatibility with iPhone Apps - Most of the applications that run on the iPhone and iPod Touch will work on the iPad at a rudimentary level, but the experience ranges from merely "ok" to downright awful. Half of the apps won't rotate to work in landscape mode. That alone is beyond frustrating. Many of them don't scale well to the larger screen of the iPad. And many have features that are missing and/or don't work on the iPad. For example, links can't be accessed from within Tweetie2. The iPhone may have access to 140,000, but the iPad doesn't. iPad-optimized apps are a must.

2. Moving Home Screen Icons - The iPad's home screen can be loaded with 20 applications on the main screen plus six apps that permanently reside at the bottom. When the iPad is held vertically, there are five rows with four apps each. When you rotate the iPad on its side, the apps rearrange themselves into four rows with five apps each. Why is this a big deal? It means you can't get used to where an application is on your home screen because it is constantly moving from row to row. If you have arranged your apps in nice, neat rows, they become jumbled with apps dropping all over the place. It's an obsessive's nightmare.

3. Not Enough Control Over App Behavior - The three main productivity applications being offered to the iPad -- Apple's Pages, Keynote and Numbers -- don't allow users to tweak settings or make adjustments to some of the default behaviors. Have a preferred font or style? You'll have to re-set it every time you start a document. Also, Keynote only operates with the iPad on its side.

4. No Local File Directory - This is a major issue for those who might want to use the iPad as a laptop replacement. There is no way for users to search through all the files stored locally on the iPad. All those nifty Numbers, Pages and Keynote documents you created can only be found from within the application itself, not launched from a file folder. This limitation also affects the email program, and how it handles attachments. It also means you can't share files via Bluetooth.

5. Wonky Tab Behavior In Safari - The iPad's Safari browser supports tabs, but not in the traditional sense. With normal desktop browsers, tabs run across the top of a window, allowing users to quickly jump from site to site to site. As someone who primarily works within a browser environment, I often have a minimum of a dozen tabs open at any given time. The iPad supports up to nine open sites at a time, but in order to get to them you have to use the tab tool to minimize the current window. Safari then show the nine open tabs and you have to select one to open it. This system works, but it really slows down browsing when jumping from tab to tab quickly is necessary. It would be nice if there were a tool that allowed users to quickly cycle through the tabs quickly, or even real tab support across the address bar.

6. Bonus! No Landscape Dock Support - The iPad's proprietary 30-pin connector is on the bottom of the device. The connector can be used to dock the iPad so that it stands up nicely while charging or during use. The problem with this is that the iPad stands up vertically in the dock, not on its side. Most display screens -- whether 4:3 or 16:9 -- are oriented in the landscape / horizontal fashion. Working with the iPad in the vertical/portrait orientation simply feels unnatural. I wish there were a second 30-pin dock connector on the side to allow for horizontal docking.