When using the open url feature pinegrow just sits there and gives no sign it is doing anything. This maybe due to long pages generated by my testing environment but there should be some notice or sign presented that Pinegrow is actually doing something.
When you initially load Pinegrow there is the open url option. If you click this and enter a URL the url will show in the recent files list but then Pinegrow just sits there. I then click the url multiple times which I do not know what that does in Pinegrow, eventually it will open to the work environment and the page loading will appear on the page view. This takes a long time to get to that page though.