cnoremap <expr><enter> (getcmdtype()=='/' ? "\n:redraw" : "\n")
I am intercepring the <enter> in the /pattern search. When search is found, it works. E.g., type /.<enter>, and you see :redraw as a sign that mapping worked. But when search was not found, this mapping does not work. Why ? Type /xyzxyz<enter>, and :redraw does not appear. Why ? Yakov