Thanks for the tip. In Tips & Tricks under "Geeky Stuff",
the page titled "Window Definition" has a table of settings, one of
which says "navigation width". These settings are parameters in a
format line that begins with the term "Window Name". Lines using
this format are supposed to appear in the .HHC file, but my .HHC
file has no lines that look like this. The only line that applies
to a window says "Default window", but my attempt to add a setting
to this (the 13th parameter) had no effect. Most of the lines in
the .HHC specify either files or parameters. Rick Stone's
description seems to be in the same territory as the .HHC file, but
I can't bring the two together. Does anyone work with this
file?