As Sencha Architect doesn't support the 'null' config, using the OptimizedTab without an override doesn't seem to work.
I've attached an example project of it working, but I'm wondering why I get this error in the console:
I can see that the component is working by typing this into the console after each tab click:
TypeError: 'null' is not an object (evaluating 'g.getCount')
...and you can see the map component disappear just before the animation, so it seems to be working.
EDIT: I just found out that it must have been my list in one of the tabs had no store associated with it. I removed it and problem seems to be fixed!