Open Radar

 
Summary:
Using the appearanceWhenContainedIn: method of UIAppearance proxy, the developer is unable to reset the appearance proxy so that system sheets like the MFMailComposeViewController or MFMessageComposeViewController use the appropriate colors.

Steps to Reproduce:
1. Add a UIAppearanceProxy with a barTintColor and/or titleTextAttributes to a plain vanilla UIViewController. 
2. Add a UIAppearanceProxy appearanceWhenContainedIn that has MFMailComposeViewController and/or MFMessageComposeViewController which resets barTintColor and titleTextAttributes to nil (or to any other color). 
3. Launch either MFMailComposeViewController or MFMessageComposeViewController. 

Expected Results:
Either a) Ignore the appearance proxy entirely or b) respect all of the proxy methods, not just random ones. Prefer b), but at least a) would be consistent. 

Actual Results:
Note that while any tintColor change is respected, barTintColor and titleTextAttributes are not. 

Version:
iOS 7.0.4. 

Notes:
Current workaround via our fine friends at SO is to create an otherwise-useless UINavigationController subclass to handle styling: http://stackoverflow.com/a/11856605/681493. This seems, frankly, kind of silly vs. what I've added as expected behavior. 

Configuration:
iOS 7.0+. In iOS 6, setting the tintColor on the navigation bar proxy in the same way using the appearance proxy updates the bar's background color. My guess would be this is something that was overlooked in the migration from tintColor to barTintColor. 

Attachments:
[email designatednerd at gmail dot com if you want the sample project]