wizard_goto_step does not save form data in session

[freakent]

If the user completes some or all of the fields in a step of the wizard then avigates to a previous step (with a Submit and wizard_goto_step), the form data they have entered is lost. When they press Next to navigate back to that same step they will have to reenter all values again.

It looks like a refactoring of the POST method on the WizardView is required. Currently it checks to see if wizard_goto_step is set and redirects to that step before processing the form.

# Look for a wizard_goto_step element in the posted data which
# contains a valid step name. If one was found, render the requested
# form. (This makes stepping back a lot easier).
wizard_goto_step = self.request.POST.get('wizard_goto_step', None)
if wizard_goto_step and wizard_goto_step in self.get_form_list():
    return self.render_goto_step(wizard_goto_step)

It would provide a better user experiewnce if this method processed the form so that anything entered is saved to the session, then check if wizard_goto_step is step. Validatation checks could be missed out and only run when navigating to Next step.