Trigger onAfterCreateGroup in AA-condition according to category

Hi Kyle,
As you may remember, I have set up the category 15 to "house" group chats. I have now run into the problem that the condition does not seem to work on the trigger onAfterCreateGroup.

I am trying to set up the condition:

Conditions
Field: Custom > Value
Custom Value: [var2_category]
Operator: Not equal To
Value: 15

Problem is that [var2_category] does not seem to come through. I have tried searching in your documentation but I am getting

$_PLUGINS->trigger( 'gj_onAfterCreateGroup', array( $this ) );

What is $this? Any possibility to get content of the variable $this quickly (for next time when I am stuck at an AA)?

For onAfterCreateGroup use [var1_category]. In the context of that trigger $this is the group object and accessed with var1 substitutions.