Greetings,
Since there's been no recent update to Safari, your problem couldn't possibly be and "anti-feature".
So, are you certain you don't have any third party Input Managers or plugins installed for anything at all? If so, one or more of them could be the cause of the problem. Did you recently install any software, and if so, what exactly did you install? Did you try Repair Disk Permissions and then restart Safari to see if the problem can be solved that way?
Have you tried creating a new User account and testing for this problem there? If it's there, then it's a systemwide issue; otherwise it's limited to something specific in your regular user account.