At 15:45 +1000 on 11/07/2012, WordWeaver wrote about Unable To Scroll
Horizontally In HTML Document:
You say you have been able to copy and paste to create a new file but
it has the same symptoms. Try using markup->utilities->format to
reformat the copy (use plain). This will preserve the original
version. Now try editing the reformatted copy. Also Check Document
Syntax on the original to see if it spots any problems.
If you want to remove a tag, why not just do a find/replace? If the
tag exists more then once, do a find until you get to the correct
version than do the replace with blanks.
Note that I know this does not find the cause but you are asking for
a Quick&Dirty solution to fix the file and either of these may meet
your needs.