Two button callbacks were identical, moved into one method
Removed hardcoded CSS class, no longer necessary in 2.11
Performance improvements in product callbacks

Unsetting operations if they cannot exist in the first place
(no product type with a certain configuration).
Massive improvement on the number of queries

No longer query for children if a product does not have any.
In my case the query count came down from > 300 to less than 100 queries.