问题
This question applies to Xcode 3 and 4: Why does this checkbox appear twice? (under the Identity inspector and also under the Attributes inspector). And more important, howcome changing the value of one doesn't affect the other?
回答1:
The User Interaction Enabled in the Identity Inspector is referring to the Accessibility protocol. Here is a link to the Accessibility Programming Guide You tick different traits to modify how the elements responds to the Accessibility systems on the device.
On the Attributes Inspector, the User Interaction Enabled is applying to non-Accessibility interaction with the particular element.
If you're wondering about why to bother with Accessibility, here is a good Matt Gemmell post on why it matters.
回答2:
One is for the main functionality in app, and one (under Accessibility in identifier inspector) is for enabling some features for people with disabilities.
来源：https://stackoverflow.com/questions/5603867/xcode-why-does-user-interaction-enabled-appear-twice