In previous versions you could enable them with maxscript. AFAIK, the tab panels aren't in Max8 -at all- now (tried toggling them with script earlier today; no dice).
phew... well yes, that shelf was "the shit" in magma/R3 back in the day. i love it, too, but autodesk disabled it by default around R6 for "performance reasons" afair. so now, every upgrade is a pain. i usually manage to do it by copying over my old settings files from a R4/5 install and hacking those. the functionality is…