message: Use struct for ProductListBoxItem
diff: @@ -16,11 +16,8 @@ class ProductPool;
  class ProductListBox : public ListBoxBase
  {
  public:
  - class ProductListBoxItem : public ListBoxItem
  + struct ProductListBoxItem : public ListBoxItem
  {
  - public:
  - ProductListBoxItem() = default;
  -
  std::size_t count = 0; /**< Count of the product. */
  float usage = 0.0f; /**< Usage of available capacity. */
  };
  