Yet I found that a serious bug in iOS 6.1.2 ,I'm not sure if it will happen in other iOS 6 version,for I've stay in this version in the longest time.The bug is that when you keep some labels in safari and haven't close them , and minimize the safari ,then try to use some other apps, especially some big apps, then when you back to safari ,sometimes you may find there is a residue shadow(I don't know the vocabulary, and I search the dictionary , it seems to be called ghost) and after a second it will disappear,and if it appears ,every time you open the safari it will appears.
The solution is open an online video in safari ,make it fullscreen , click the Home button ,and open safari again ,you can see the residue shadow has disappeared.:)
The solution is open an online video in safari ,make it fullscreen , click the Home button ,and open safari again ,you can see the residue shadow has disappeared.:)