Directory indexes in navigation

[lrem]

Right now navigation incorrectly links always to .html files, even if it is meant to point to a directory index. This probably can't be solved client-side, where the code resides now.

[lrem]

It is not clear if this is incorrect. In my own websites the current behavior was always the expected one. Probably the best thing to do is to make this another configuration option. However, what should be the option's name?