I have found this too. There is some kind of bug with selecting titles. I don’t need full DVD menu utilization, but title and chapter support is a glaring and surprising omission.
A simple solution is needed. When you call up the info bar there should be next to the (not functioning) chapter section, a title section. The chapters don’t need to be on the info bar, it isn’t functional there anyway, and should be on the skip forward and skip back buttons on the remote. The titles, of which there are always many fewer, should be on the info bar.
Menus are bothersome but an elegant way to deal with chapters would be to use the skip and back on the remote, and a “Title” selection on the info bar instead of Chapter.