Method ClearItems

imgui_tiny_app/imgui/imgui_demo.cpp:11106–11110

        RequestSort = true;
    }
    void ClearItems()
    {
        Items.clear();
        Selection.Clear();
    }

    // Logic would be written in the main code BeginChild() and outputting to local variables.
    // We extracted it into a function so we can call it easily from multiple places.