You developed an OutSystems WebApplication that needs to navigate to an external URL out of your control (e.g. OutSystems’ website), but afterwards the user decides to use the browser’s back button. What is the expected behavior? Will the browser re-render the page? Or should the preparation​ ​also​ ​be​ ​re-executed?

The behavior we observe is probably not what you’d expect: although the preparation of your web screen is not executed, the browser does re-render the page. In other words, the page is rendered with the information saved in the browser’s cache. Every time you make a request to the server using the ​Submit method the browser caches the response. This however does not happen if you use the ​Ajax Submit method. And what if proper display of your web screen requires the preparation to execute some business logic that affects what or how you show something​ ​to​ ​the​ ​user? 

In order to run the preparation after coming back from an external URL (by clicking the back button on the browser) you need to force it to happen.