Overcoming the synchronous web copy/paste API's limitations in real browsers is extremely non-trivial. Come & hear how we provide rich copy/paste support across browsers, inside our app and hear a bit about how this mess should be fixed. Collabora has been working to provide a good user-experience for Collabora Online - bringing LibreOffice to the web, and a particularly challenging aspect of this has been copy/paste. One of our challenges is that by design we keep our document data on the server, which is at the end of an asynchronous web-socket. Another challenge is the impossibly baroque and arguably mis-designed set of clipboard APIs that we have to work with. Hear a story of how we defeated the issues, as well as the somewhat sad UX compromises we were forced to make for the hard cases.