ScrollBar weird scaling

Hello.

There are some themes already discussed about ListView or ScrollView. And I looked them through.
However I do not understand my case where the scrollbar of a ListView element is scaled to occupy the whole size of its parent.
My snippets:

Creating ListView:

listView_ = CreateChild<ListView>();
listView_->SetLayout(LM_VERTICAL, 6, IntRect(6, 6, 6, 6));
listView_->SetAlignment(HA_LEFT, VA_TOP);
listView_->SetMinSize(100, listView_->GetParent()->GetHeight());
listView_->SetMaxWidth(listView_->GetParent()->GetHeight()*0.7f);
listView_->SetMultiselect (false);
listView_->SetHighlightMode(HighlightMode::HM_ALWAYS);
listView_->SetStyle("ListView", cache->GetResource<XMLFile>("UI/DefaultStyle.xml"));
listView_->SetStyleAuto();

Adding elements to ListView:

ListElement listElem;

ResourceCache* cache = GetSubsystem<ResourceCache>();

Window *element = new Window(GetContext()); //content_->CreateChild<Window>(); //// new UIElement(this->GetContext());
listElem.bodyElement_ = element;
element->SetLayoutBorder(IntRect(5,5,5,5));
element->SetLayoutMode(LM_VERTICAL);
element->SetLayoutSpacing(2);
element->SetMaxHeight(80);
element->SetWidth(listView_->GetWidth()*0.8f);
element->SetStyleAuto();
// listView_->InsertItem(index, element);
  

// Create the Window title Text
listElem.titleBar_ = element->CreateChild<UIElement>();
...    
listElem.titleText_ = listElem.titleBar_->CreateChild<Text>();
...    
listElem.removeButton_ = listElem.titleBar_->CreateChild<Button>()
...    
listElem.textVector3_ = element->CreateChild<Text>(); 

listElem.titleBar_->SetStyleAuto();
listElem.titleText_->SetStyleAuto();
listElem.removeButton_->SetStyle("CloseButton");
listElem.textVector3_->SetStyleAuto();

//listView_->InsertItem(index, element);
listView_->AddItem(element);

I faced exactly the same issue with ScrollView.
Do not call AddChild, SetLayout or other behavior-important UIElement methods for compound UI elements like ListView, ScrollView and so on.

Indeed commenting out the second line

      listView_ = CreateChild<ListView>();
      // listView_->SetLayout(LM_VERTICAL, 6, IntRect(6, 6, 6, 6));
      listView_->SetAlignment(HA_LEFT, VA_TOP);
      listView_->SetMinSize(100, listView_->GetParent()->GetHeight());
      listView_->SetMaxWidth(listView_->GetParent()->GetHeight()*0.7f);
      listView_->SetMultiselect (false);
      listView_->SetHighlightMode(HighlightMode::HM_ALWAYS);
      listView_->SetStyle("ListView", cache->GetResource<XMLFile>("UI/DefaultStyle.xml"));
      listView_->SetStyleAuto();

solved it: