Vista "Delete browsing history" window

Using vista sp2 beta (tried with sp1 as well), when the box is checked for "Recently Typed URLs" and "Autocomplete Form History" under the cleaner section, windows tab, the "Delete browsing history" window pops up and takes anywhere from 5 to 10 seconds to complete. When "Recently Typed URLs" is unchecked, it only takes about a second. When "Autocomplete Form History" is also unchecked, it doesn't come up at all. For me at least, this seems to be rather new behavior and obviously, the answer is to uncheck the items if the window and delay bothers you. Just checking to see, asking, if down the road in new builds this type of cleaning can be done another way besides invoking IE's method so no pop up windows. Thx