If I modify a value in interactive grid and hit the save button the value is submitted and the current page state remains intact. However if I modify a page item value in a form and submit Apex will always reload the page. Why ? Since 5.1 submit is implemented using AJAX yet the only options on the 'reload on submit' page property are 'Always' and 'Only for Success' - in other words always reload unless an error.
Is there a good reason for not having the choice to submit without reload and is there a way (without writing own callback functions) ?