Generating Layered Sidebar table of contents in the Mobi sidebar

it seems to be working in the previous version. but after upgrading to the newer version, i cannot generate layered sidebar table of contents in mobi.

i want to find a way to generate TOC in the sidebar that have folder as level 1, page title in the folder as level 2. is this still feasible?

btw, it seems pdf outline works fine in the new version. thanks for the fix.