Here are some things to try if you can't see a page you have created in link dropdown lists.
1. Have you tried clearing your web browser's cache?
Sometimes when you create a new page you will have to clear your browser's cache so that the browser will be able to display the new page in link dropdown lists. This is not a fault of Perpetua or your website, it's just a limitation of the internet as it only refreshes that cache every so often. This speeds up the way browsers work so that it doesn't have to reload everything every time you re-visit a webpage.