sorting files vista windows explorer

When using windows explorer I am used to sorting a folder with a large number of files by date modified so that I can quickly access the most recently modified files. However in Vista beta 2, things have changed. I have a large number of zip files in this folder and explorer now groups all the zip files first and sorts them by date modified, followed by all the other files in date modified order. The XP version of explorer did not group the zip files first and sorted all by date modified. Is there a way in Vista to sort all the files by date modified and NOT have the zip files listed first as a separate subgroup ? I have tried experimenting with the new Vista sorting options "stack" and "group" but have been unsuccessful.