I solved it on mine
I've got same problem yesterday, after multiple automatic updates from the google play - app drawer icon and all custom icons disappeared from the dock. I replaced custom icons, but wasn't able to get app drawer icon back and could access the drawer.
there is no launcher settings in the menu, nor in the desktop options, and even in the launcher options in the system settings there is no option to bring back the app drawer icon. force-stopping launcher, restarting phone, cleaning cash and even dalvik cash doesn't help either.
the only way to bring it back that worked, was clearing all data for trebuchet :
- menu button > manage apps > trebuchet > clear data
however (!) when you do so, everything you have on your screens will disappear
, and you will have to customize your screens again and recreate all shortcuts, widgets and folders.
I wonder why it happened and if there is way to fix it without loosing your customization.
---------- Post added at 04:17 PM ---------- Previous post was at 04:09 PM ----------
I didn't run titanium backup after latest ROM flash, thus I didn't have a backup for trebuchet, but if you have it, try to restore data for trebuchet. I'm sure it would be easiest solution