from the web, http://beta2013.bitdefender.com/
"We've listened to our valued Beta testers and are responding by making Bitdefender 2013 compatible with Malwarebytes so you can use both products at the same time."
And here on the forum we got info from support that
"We do not recommend you to run another antivirus or anti-malware product near Bitdefender."
But isn't it seems some sort of dissatisfaction that the user can installed two antimalware softwares? Can't we rely on bitdefender alone to keep our computers secure. Its a bad impression of the company to suggest other similar product to use with their own. It also means that Bitdefender lack in protecting the computer in some way, and this lacking can be overcome by using Malwarebytes along with it....wow...instead of improving their product and to overcome its deficiencies, an other product is suggested......thats cool......isn't it. 
I don't want to insult anyone....rather i suggest that the bitdefender alone should be capable of securing the system....and....Bitdefender team, you should build the confidence of the user about using your own product assuring them about their computer security, not by making your product compatible with others.
Bitdefender has already three layers of active protection i.e. Signature, Heuristics, and AVC.
And I consider the Technical Support as FOURTH Layer protection.