I have recently discovered a bug in HTMLHelp regarding spaces in a HTMLHelp file name (.CHM file).

If you issue:

  SET HELP TO "ABC.CHM"
  HELP

then go back to FoxPro (leave the first help file open), and issue :

  SET HELP TO "DE F.CHM"
  HELP

the help system will lock up and you will have to close the second help file with a CTRL-ALT-DELETE.

The same thing happens if you use the HtmlHelp() API function (in both Visual FoxPro and Visual Basic) instead of the SET HELP/HELP combination.

Just wanted to let everyone know in case they have spaces in their .CHM file names. Since I haven't seen this documented anywhere, I'm going to submit this to Microsoft as a bug.