These options control how ProOptimizer treats vertex sub-object selections. You can’t create a sub-object selection in ProOptimizer, but it can acquire a vertex selection from an object or modifier below it on the stack.
Modify panel > Modifier List > ProOptimizer modifier > Optimization Options rollout > Sub-Object Selection group
When on, ProOptimizer does not optimize vertex selections passed up from the stack. When off, ProOptimizer disregards vertex sub-object selections. Default=off.
When on, ProOptimizer optimizes the vertex selection and disregards the rest of the object. Default=off.
This control is unavailable unless Preserve Vertices is turned on.