Currently, a Form's ValidationTracker inherits the default persistence strategy. The result is that by default the session becomes littered with ValidationTrackerImpl objects as you move from page to page.
In response to this problem there have been several workarounds proposed in the mailing lists. They all involve making the ValidationTracker use "flash" persistence.
Consequently, I'm proposing that we make "flash" the default for Form's ValidationTracker so we can all forget about it. After all, it would be very unusual to want a form's validation errors to be retained after the form has been displayed, regardless of what persistence strategy makes sense for any other component of the form.
If there remains a situation in which it makes sense to override it, then perhaps that could be possible through a new parameter of the Form component.