Here are two things you can do:
(1) Download the FREE AppDrawer app from Google Play.
It gives you a shortcut to the app list.
However, it does not give you the widget list.
(2) Reset Trebuchet.
NOTE: Use the procedure below at your own risk.
It clears (or resets) the contents of your home screen.
CM10.1 uses the Trebuchet launcher.
From your homescreen,
press the left menu button, and select
Look for Trebuchet, and click it.
Clear data button.
Alternatively, you may find success (without having to repopulate all of your home screens) via simply selecting "Clear Cache" and then "Force Stop" on the Trebuchet apps menu.