Thanks for this, MEB. It's good to know why at least. Sorry if I underplayed the difficulty of extension. I guess I'm just frustrated as I'm an affinity fan. I know this feature would be so helpful for future users, as an API would benefit many plugins not just astute graphics, and lastly can I recommend adding a feature to measure paths both lines and curves, as that is what started this query. Unfortunately, whilst being a huge fan of affinity, have had to subscribe to adobe (yuck) in order to make my vector-based sewing patterns and will use astute graphics plugins (VectorScribe mainly). :O( I hate supporting Adobe in any way. However, I will continue to do some work in Designer to keep current, and keep an eye out on your update news - hopefully one day you will extend the range of features. Thanks