Flag 32 on NiSwitchNode and its subclases, like NiLODNode, causes only active branch to compute. In some cases can have immense performance gain. In others, like looping particle systems, the opposite, but there it will be visible at glance if looping breaks. Add Flag choice window to this type of node with explanation what they do.
1 (NiAVObject::AppCulled)
2,4 (NiAVObject::PropagateMode)
8 (NiAVObject::Visual)
16 (NiBSPArrayController::AtVertices)
32 (NiSwitchNode::UpdateOnlyActive)