When I drag a file from the Finder into the project in XCode, Xcode will sometimes (but not always) check the Target Membership check box. Sometimes when I drag a group of files, some will get added to the target and some won't. If this happens for resource files (media files, xibs, etc), this can be really tough to track down.
How about an inspection that finds all files that are in the project but aren't a member of any target, or aren't a memeber of a specific target? Header files would have to be automatically excluded from this inspection, of course.
Is there any way to handle this now in AppCode? If not, I'll file an issue.