Triggers misbehaving

Hi all,
I am experiencing some strange trigger (mis)behaviors. I have a large level scene with a lot of objects. To improve performance, I am setting up "culling triggers" - when the player is in the trigger, objects are enabled. When the player is not in the trigger, objects are not enabled. It mostly works and my framerate has gone from 25 to 50fps. However, I am getting some weird crashes and object flickering.

Here is the logic I'm using:
1) Objects have two flags "cullee" (can be culled) or "culler" (i.e. the player)
2) On enter, "cullee" objects are added to a simset for that trigger
3) On enter, the "culler" object enables all objects in the simset.
4) On exit, the "culler" object disables all cullees within the simset.


This works 80% of the time, but I have two strange problems:
1.) Creating the simset in the "onlevelLoaded" callback crashes the game. I've done this in other behaviors without any problem.
2.) At certain spots within the trigger relative the cullee object, the player starts firing both the "onLeave" and "onEnter" callbacks. This causes the culled objects to flash on and off.

I am most concerned about #2. Anyone have any suggestions?


Here is the behavior that I'm setting on the trigger:

if (!isObject(cullBehavior))
{
   %template = new BehaviorTemplate(cullBehavior);
   
   %template.friendlyName = "Cull objects";
   %template.behaviorType = "Trigger";
   %template.description  = "Cull objects within the trigger's area";

}

function cullBehavior::onBehaviorAdd(%this)
{
   %this.owner.EnterCallback = true;
   %this.owner.StayCallback = false;
   %this.owner.LeaveCallback = true;
   %this.occupied = false;
}

//function cullBehavior::onLevelLoaded(%this, %scenegraph)
//{
   //%this.objectSet = new SimSet();  
//}

function cullBehavior::onEnter(%this, %obj)
{ 
  echo(%obj SPC %obj.config SPC "ENTERED" );
   
   if(!isObject(%this.objectSet))
      %this.objectSet = new SimSet();  
   
   if(%obj.cullee)
   {
      %member = %this.objectSet.isMember(%obj);
      
      if (!%member)
      {
         %this.objectSet.add(%obj);
      }

      %obj.enabled = %this.occupied;
   } 
   else if (%obj.culler)
   {
      %this.setEnableAll(true);
      %this.occupied = true;
   }
}

function cullBehavior::onLeave(%this, %obj)
{
  echo(%obj SPC %obj.config SPC "EXITED" );
   
   if(!isObject(%this.objectSet))
      %this.objectSet = new SimSet();  
   
   if(%obj.culler)
   {
      %this.setEnableAll(false);
      %this.occupied = false;
   }
}

function cullBehavior::setEnableAll(%this, %bool)
{
   %count = %this.objectSet.getCount();

   for (%i = 0; %i < %count; %i++)
   {
      %obj = %this.objectSet.getObject(%i);
      %obj.setEnabled(%bool);      
   }
}