You mean *.xlk?
I'm not sure you can ever get it to ignore them. But you could just show what
you want.
So the file|open dialog.
Type this in the filename box:
*.xls
and hit enter.
It's an extra step, but it's not too difficult. You could even specify more in
that string:
*book*.xls
to show only those *.xls files that have book in their names.
