Got it! When I erroneously moved the file to the desktop, I realised
that may
be the problem and started all over. But then I put the *.exc file in
the same
folder as the lex file, whereas I should have put it in the same folder
as the
custom.dic file. That cured everything. Then I created a shortcut and
dragged
*that* to the desktop for easy access, so the original file was left in
the
right directory... um... folder (difficult to lose old habits!)