It has been reported to me that there is an annoying bug for Mavericks users with the latest iObserve version 1.4.0. The "New Object" sheet doesn't appear at all. Sorry for that! I am currently fixing it and will push it ASAP to the App Store for review. In the meantime, you can use the 'Import from list' feature, in the 'File' menu (I know, this isn't as good... Pro tip: Did you know that by alt-clicking on "New Object" you were actually opening the 'Import from list' sheet?...