Hi jag,

That particular button just protects the document (with no password,
which isn't quite the same thing as a blank password, but you can
think of it that way if it makes you happy...)

You can add another button to the Forms toolbar (or any other toolbar)
to open the Protect Document dialog. Open the Tools > Customize
dialog. Select "Tools" in the left-hand list. Scroll down the
right-hand list to find "Protect Document...", and drag that entry to
the desired toolbar (see the pictures in
http://www.word.mvps.org/FAQs/Customization/AsgnCmdOrMacroToToolbar.htm
for examples). You can also drag off the lock button if you don't want
it.

The new button has only words and no icon, but you can right-click it,
select an icon, and set "Default Style" which shows only the icon.

--
Regards,
Jay Freedman
Microsoft Word MVP         FAQ: http://word.mvps.org