The deadline for Apples sandboxingfeature is from march to June shifted. Previously, that deadline been moved up to november last year. The feature should be the security of applications better, but not all developers are for.
Last time it took developers are concerned because the restrictions on reading and writing files, serious obstacles would produce. Also, there were reports of bugs in the software. Also find some developers on the platform the system is too restrictive. The various rights that an application may be appropriate would be limited, thus programs, certain features can not perform.
The sandbox feature, which is already used in iOS, that applications not perform functions or locations can access where they have no right to do so. With OS X 10.7.3 and Xcode 4.3 can the developers start to see the method in their programs to integrate.