Sorry - still broken
I just used fresh update of mac osx and firefox 2 and used your sample editor

 

create ten lines of text

enter cursor at line 5
create an anchor using the anchor tool

name it an OK
select HTML view
all content below anchor is deleted

 

when I type in an anchor as in <a name="test"/> it works and I can switch views

 

This is my biggest client grievance at the moment, well for a long time now.

Can you reproduce?