Open Radar

 
Summary:
If an app changes the brightness level of the main screen, the user-supplied brightness is not restored when said app is not in the foreground. This contradicts the documentation for the brightness property discussed in the UIScreen Class Reference:

"Brightness changes made by an app remain in effect only while the app is active. The system restores the user-supplied brightness setting at appropriate times when your app is not in the foreground. So if you change the value of this property, you do not need to record the previous value and restore it when your app moves to the background."

Steps to Reproduce:
1. Set the test device brightness to anything less than 100%
2. Build and run the attached project on the test device.
3. Set the switch to the on position - the main screen's brightness is now 100%.

4a. Press the Home button.
or
4b. Use the task switcher to switch to a different app.
or
4c. Kill the app from the task switcher.

Expected Results:
The user-supplied brightness in step 1 should be restored.

Actual Results:
The user-supplied brightness is not restored; the main screen's brightness remains at 100%.

Version:
iOS 8.4.1 (12H321)

Notes:
The test app simply sets the main screen's brightness to 1.0 upon toggling a switch.