Small validation problem with validator.w3.org

Hi,

I noticed that the validator, when it's validating XHTML 1.0
transitional, seems to complain about nested unordered list tags (<ul>).
I checked up on the HTML 4.01 specs, and it says that nested lists are
allowed.  It doesn't mention anything about nesting 2 lists of the same
type (nesting a <ul> inside a <ul>), but I'd assume that it should be
valid.

Sorry if this has already been reported.

Eli