Behavior Blocker definition according to Comodo :
https://help.comodo.com/topic-72-1-451-4767-.html
"The Behavior Blocker is an integral part of the Defense+ engine and is responsible for authenticating every executable image that is loaded into the memory. The Behavior Blocker intercepts all files before they are loaded into memory and intercepts prefetching/caching attempts for those files. It calculates the hash of the executable at the point it attempts to load into the memory. It then compares this hash with the list of known / recognized applications that are on the Comodo safe list. If the hash matches the one on record for the executable, then the application is safe and the Behavior Blocker allows it to run. If no matching hash is found on the safelist, then the executable is 'unrecognized' and is run inside the auto-sandbox. You will be notified via an alert when this happens."
Among the system protection features in Qihoo I found "Malicious Behavior Blocking" that usually generates these warnings:
"Modifying startup item" , "Modifying sensitive system setting" and "Modifying key COM component."
These messages, which should be about Behavior Blocking, honestly seem to me related to the blocking access to the Windows Registry.
In my opinion the definition of Qihoo about BB is not what I mean.