select all in not supported OTB in the optimized table version - the select all always had usability issues since it only selects the row that are visible - this works well for small set of data but does not really work if you use paging with hundreds of row.
You can always had the select all has a regular button that will set a property in an editable data.
You can look at how bulk processing is implemented using non-optimized table - this feature has been around for several releases.
if you have a clipboardPage - in this example called pyBulkProcessingPage, this can be achieved by adding a checkbox in the 1st column header - the checkbox uses the property pyBulkProcessingPage.pySelected and does a post value on the property and refreshed list
configure the update grid activity pyPreGridUpdateForBulkProcessing
here is the activity
the advantage of this approach is that the DP on the server will be updated with the selected rows - if the browser is refreshed, the selection is persisted. You could also achieve the selection purely on the client side using a simple JS loop to select all the checkbox but the selection will be client only and not persisted on the server until the next form submit
I could have made questions clear :). I was actually referring to implementing the select all feature in optimized grid. Our clients are very much interested in having the group by, column selection feature but we had to fallback to unoptimzied grid just because the select all could not be implemented.