xpNegate General tab
Checking this box enables the xpNegate modifier.
Set at Independent, by default.
You can change this to Action-Controlled.
In this mode, particles will be affected if they come into the field of effect of the modifier.
When in the Action-Controlled setting, the modifier will only act on a particle when told to do so by an action.
This value can be used to add some random variation to the modifier effect.
It is the probability that the modifier will negate the selected options when the particle is within its field of effect.
If set to 100%, the effect will always occur; if it is 0 (zero) %, it never will.