Not sure if this is new or not but I just stumbled upon this, when your auditioning loops in the browser hold cntr and keep clicking loops in the browser and they will all play in sync if you have preview at host tempo , and loop preview on.. Pretty cool it saves you a little time if you wanna see how a few loops sound good together without having to drag in and out ,and adjusting volume .
If You Hold down Control you can select and deselect loops.
Probably had this feature in sonar 2.2 but i just found it..