by H.G.Muller » 05 Mar 2019, 08:50
This happens because WinBoard tries to first start the old Windows Help viewer on the old help file, and when that does not succeed, opens the new viewer to show the chm file.
Unfortunately MicroSoft at some point installed a system where starting the old Help viewer always 'succeeds', but where success was redefined as showing this web page, rather than the .hlp file. WinBoard of course does not know that it launched a defective .hlp viewer, so it never gets to start the .chm viewer.
I guess the solution should be to abandon the .hlp support altogether, and have WinBoard always and only attempt to show the .chm file.