Why don developers just put in copy / paste themselves?
Applications are not allowed to run in the background. This means that once the text is copied from an application, leaving the application to paste in another will close the clipboard where the text was being held. Also, due to Apple’s sandbox effect, developers cannot create plug-ins to interact with other applications. But OpenClip, a technique developed by Zac White, uses a different method. Now, by using the OpenClip framework, developers have the ability to implement copy / paste in their apps.