message: Remove `using namespace NAS2D;` from `ComboBox`
diff: #include <algorithm>
  -using namespace NAS2D;
  -
  -
  ComboBox::ComboBox() :
  UIContainer{{&btnDown, &txtField, &lstItems}}
  {
  - auto& eventHandler = Utility<EventHandler>::get();
  + auto& eventHandler = NAS2D::Utility<NAS2D::EventHandler>::get();
  eventHandler.mouseWheel().connect({this, &ComboBox::onMouseWheel});
  btnDown.image("ui/icons/down.png");
  @@ -33,7 +30,7 @@ ComboBox::ComboBox() :
  ComboBox::~ComboBox()
  {
  lstItems.selectionChanged().disconnect({this, &ComboBox::onListSelectionChange});
  - auto& eventHandler = Utility<EventHandler>::get();
  + auto& eventHandler = NAS2D::Utility<NAS2D::EventHandler>::get();
  eventHandler.mouseWheel().disconnect({this, &ComboBox::onMouseWheel});
  }
  @@ -57,7 +54,7 @@ void ComboBox::onResize()
  lstItems.width(mRect.width);
  lstItems.position(rect().crossYPoint());
  - mBaseArea = Rectangle<int>::Create(position(), NAS2D::Vector{mRect.width, btnDown.size().y});
  + mBaseArea = NAS2D::Rectangle<int>::Create(position(), NAS2D::Vector{mRect.width, btnDown.size().y});
  }
  @@ -72,17 +69,17 @@ void ComboBox::onMove(NAS2D::Vector<int> displacement)
  btnDown.position(txtField.rect().crossXPoint());
  lstItems.position(rect().crossYPoint());
  - mBaseArea = Rectangle<int>::Create(position(), NAS2D::Vector{mRect.width, btnDown.size().y});
  + mBaseArea = NAS2D::Rectangle<int>::Create(position(), NAS2D::Vector{mRect.width, btnDown.size().y});
  }
  -void ComboBox::onMouseDown(EventHandler::MouseButton button, NAS2D::Point<int> position)
  +void ComboBox::onMouseDown(NAS2D::EventHandler::MouseButton button, NAS2D::Point<int> position)
  {
  UIContainer::onMouseDown(button, position);
  if (!enabled() || !visible()) { return; }
  - if (button != EventHandler::MouseButton::Left) { return; }
  + if (button != NAS2D::EventHandler::MouseButton::Left) { return; }
  if (mBaseArea.contains(position))
  {
  @@ -189,7 +186,7 @@ void ComboBox::setSelected(std::size_t index) {
  void ComboBox::text(const std::string& text) {
  txtField.text(text);
  - lstItems.selectIf([target = toLowercase(txtField.text())](const auto& item){ return toLowercase(item.text) == target; });
  + lstItems.selectIf([target = NAS2D::toLowercase(txtField.text())](const auto& item){ return NAS2D::toLowercase(item.text) == target; });
  mSelectionChanged();
  }
  