"Morning all! I've been tinkering..." <- 1. I can see why you might want to put the original value in the JSON in order to confirm that you are replacing the correct value, but that would be a very specific use case and not the general one where only the new values are needed. The JSON should be simplified to just be `{"title": "Waterloo", "artist": "ABBA"}. 2. I think you need to handle values as both arrays as in your original JSON and plain strings as in point 1. 3. This JSON is limited to a single track which makes sense for pasting into the metadata area of a single selected track. But do we want to extend the paste to copying to multiple selected tracks, and if so then A) should this be limited to album-related metadata and B) do we want to extend the JSON schema to allow for several tracks specific data to be specified using e.g. some sort of MBIDs (which IMO will be complicated and shouldn't be attempted at this point - but you should make sure now that the JSON schema can be extended later). 4. I am not sure that I agree with @outsidecontext's suggestion to use QT's special clipboard functionality - users **will** want to copy and paste between applications, so you want to have compatibility here - and that means either using a pre-defined JSON clipboard type or even thinking about implementing several common clipboard formats e.g. plain text, JSON, perhaps a spreadsheet-specific format or XML too or perhaps there is a key/value pair format. 5. Preserving Copy backwards compatibility probably should mean **NOT** copying JSON to the plain clipboard, but instead only by default to the JSON specific clipboard. That will also likely mean that we will need a context menu to copy JSON to the plain clipboard. 6. We will also need to preserve Paste backwards compatibility and deal with several different types of Paste contents. So you probably need to analyse what tracks are selected to be displayed in the metadata area, what metadata rows are selected and whether there is an edit box open and combine that with analysis of the possibly several types of paste data available on the clipboard before determining which data and what type of paste to do - and you probably want to warn the user if they are about to paste album data across several albums or track data across several tracks.