Why does Selection disappear after Apply?


I ve created selection using, including, this:

  vtkSMProxy* selectionSource = repr->GetSessionProxyManager()->NewProxy("sources", "IDSelectionSource");
  vtkSMPropertyHelper(selectionSource, "FieldType").Set(vtkSelectionNode::POINT); // vtkSelectionNode::POINT
  vtkSMPropertyHelper(selectionSource, "IDs").Set(IDs, ids.size() * 2);

It works fine and is visible.

However, after I click Apply, it disappears, and the same code that produced selection before apply, does not work after it.

I am desperate about it, and have no clue

Help me, please