your proposal isn't fixing the problem, it just hides it
what seems (to be confirmed) to happen is that winhelp should better support secondary windows as 'glossary' (or have fallback for those) as it does for primary window (called 'main') (or support defining window name when opening a file)
can you send me (in private) the relevant .hlp files (main one and glossary.hlp) I'll have a deeper look