UnityEngine.GUILayoutUtility.BeginWindow C# (CSharp) Method

        internal static void BeginWindow(int windowID, GUIStyle style, GUILayoutOption[] options)
        {
            LayoutCache cache = SelectIDList(windowID, true);
            if (Event.current.type == EventType.Layout)
            {
                current.topLevel = cache.topLevel = new GUILayoutGroup();
                current.topLevel.style = style;
                current.topLevel.windowID = windowID;
                if (options != null)
                {
                    current.topLevel.ApplyOptions(options);
                }
                current.layoutGroups.Clear();
                current.layoutGroups.Push(current.topLevel);
                current.windows = cache.windows = new GUILayoutGroup();
            }
            else
            {
                current.topLevel = cache.topLevel;
                current.layoutGroups = cache.layoutGroups;
                current.windows = cache.windows;
            }
        }