When to reset fields in a custom insert page?

Question

Hi
In Apex 3 I have a page with fields to insert a new record. The first time the page is loaded (clicking a button in another page) I reset all the fields using a Before Header process (so the user doesn't see the previously entered data). The user can then insert data in the fields and click the "Add record" button.
Using conditional branches, on submit I control if the page branches to the calling page or to itself, depending on the success of the operation.
The problem is that, if the operation fails, when the page reloads all the data the user entered is cleared, instead of remaining there to be corrected!
This must be something stupidly basic but I have no idea how to handle it. What is the standard/recommended way to achieve this? Any suggestions will be welcome!
Thanks
Luis

Answer 1

Hi Denes
Yes, the setting is "Only when current value in session state is null".
However, none of both available options for that property is what I need. When the user navigates to that page from another page I want the items to be reset. However, if the page reloads because the processing failed (i.e. the page branches to itself), I want the items to keep their previous values so the user may correct them.
To solve it, I created a page variable called "reset" that indicates that the page variables must be reset and should be set to Y by the calling page. I set it to N in a Before Header process so if the page reloads the variables will not be reset.
But I am not sure if this is the correct way to implement this or if there is a simpler way, because I am sure this must be something very common and trivial for web applications (to which I am quite new).
Thanks
Luis