As reported by GotoFinal in https://github.com/bdunderscore/modular-avatar/issues/1408#issuecomment-2599998015 - VRCPhysBoneEditor calls EditorUtility.SetDirty right after calling ApplyModifiedProperties on the editor SerializedObject. This is redundant, as SerializedObject handles setting objects dirty, and also broken in that it only hits the _first_ target in a multi-select.

Calling SetDirty generates a event on the ObjectChangeEventStream; a well-behaved editor plugin would then need to scan the entire scene for changes, and this scanning resulted in performance issues in NDMF and Modular Avatar. Given that this SetDirty call isn't needed, please remove this call to avoid generating these unhelpful ChangeScene events.