dont invalidate layout if section doesnt exist, fixes #304
dont invalidate layout if section doesnt exist, fixes #304

joerocca/GitHawk,rnystrom/GitHawk,rnystrom/GitHawk,rnystrom/GitHawk,rnystrom/GitHawk,joerocca/GitHawk,joerocca/GitHawk,joerocca/GitHawk,rnystrom/GitHawk,joerocca/GitHawk,joerocca/GitHawk