I feel we need to have the search be as accessible and intuitive as possible. If someone searches for something using the provided search box, it should by default return relevant result for almost any keyword. With "part number and description" as the default, if you, for example, search for a Bricklink number you'll get nothing even though that part may exist in the library. This is why I changed the default to "header". I felt this would solve the problem nicely since all of the relevant information for a part is there.
As to the search box pointing to ptdetail instead of ptscan, I'll revert that.
As to the search box pointing to ptdetail instead of ptscan, I'll revert that.