Breakpoints in MonoBehaviour code called from SmartFoxServer2X.dll cause Editor debugging hangs.

Some of my C# code is called from the SmartFoxServer2X.dll (C# dll) and placing a breakpoint there when debugging causes the editor to hang. I think that it must be running on it's own thread. Is there a special step to debug these callbacks? I'm using Unity 4.5.1 Pro in the Editor on a Windows computer.