I'll look into adding a "Clear Recent" option to both recent items menus.  There is a complicated way to remove the lists, but it is not a supported function and can possibly lead to instability.  If you're really set on clearing the lists, I can provide some guidance via email.

Even an option to reset the list (removing all entries) would be good, as long as it didn't remove the new projects list for installed packages.

Jeff, I recall you once told me where I could find the stored data which I could edit manually, though I can't now recall where that was.
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John