There's an annoying bug I noticed in Safari in iOS 7 on my iPad 2 that causes Safari's controls (back/forward buttons, URL bar) to get pushed up into the status bar. I happen to use my iPad 2 in a leather case with a flap so I basically use the iPad 2 upside down, with home button on top.
Here is how you reproduce it:
1. Hold iPad in portrait mode with the home button on top
2. Open Safari
3. Visit a video sharing website such as YouTube or Liveleak and play a video.
4. Enter full-screen mode within the video and then exit it.
5. You will find the upper portion of Safari and the status bar overlapping.
To correct the overlap you rotate the iPad in any direction, enter full-screen again and then exit it. I'm not a developer so I hope someone else will eventually bring this to Apple's attention, if the bug is not yet know.