Indexes are not sorted alphabetically in CHM output

When I export to a CHM file, the index sorting is NOT alphabetical as shown in the Index Designer. Now get this -- when I export to WebHelp, the Indexes ARE sorted alphabetically as shown in the Index Designer. And when I open the HHK file in a text editor, I see that it mirrors the strange sort I see in the CHM file.

Does anyone know how to fix this so that CHM indexes are sorted alphabetical as desired and shown in the Index Designer? Is there a way to rebuild the HHK file so that it is sorted correctly? Thanks in advance,
Gary