I tested incremental index options for mod_autoindex and I wonder whether I understand the documentation, whether it works as designed or whether I hit a bug. Right now I'm just confused.

As far as I understand, IndexOptions are applicable on the server config level or within 'directory'. Since nothing else is stated, I expect same results:

=== variant A ===
IndexOptions +XHTML
<Directory /foo>
Options Indexes
</Directory>

=== variant B ===
<Directory /foo>
Options Indexes
IndexOptions +XHTML
</Directory>

This is not the case. Variant A does NOT enable XHTML while variant B does.

The documentation states also that multiple index options for a single directory now merged together. 

** I believe that the documentation forgot to mention that incremental options only work on a "single" directory and not on a server config level. **

However: I can only speculate about the reasons why there should be a difference on handling options on a server config or on a directory level. To me, and I truly hope I'm not the only one, makes this difference no sense at all.