G3/400 B&W, 896 Mb of Ram, MacOs 9.2.2, all apple softs are up-to-date. When Mozilla 1.0 Release Candidate 3 (Mozilla/5.0 (Macintosh; U; PPC; en-US; rv:1.0rc3) Gecko/20020523) is on, I can not type letters in Sherlock and sometime Internet Explorer 5.1 and even sometime with Mozilla itself. Other softwares doesn't have this trouble.
This sounds like bug 130852 (filed by me). I have the same problem with Sherlock, Outlook Express 5.0.4, FreeHand 10, etc.
*** This bug has been marked as a duplicate of 130852 ***