Find duplicate: 'search for' box '*' autofills

I am in the find duplicate panel
In the find in: x:... is entered
then in the search for I wanted to enter *.txt.

The moment I enter the '*' character, it autofills
"C:\Documents and Settings\Namel\Favorites"

I cud enter anything else there, like .txt but the * seems to be allowed there.

Obviously I cud also use 'Filter' and enter *.txt there.

Just think it a bit strange though. Closed down DO and launched it again,
same thing.
Maybe it is normal, but as a simple end-user I wud expect that *.txt shd be allowed.

==

The Search For list is to let you search for duplicates of particular files (file path to a file, and its contents may be used as part of the search), not to filter the list by name.

Thanks a lot!