Unity's GUI, Editor and GUILayout and EditorLayout

Difference between GUILayout and EditorLayout in Unity. What is difference between GUI and GUILayout? GUI uses fixed layout which means every gui elements needs specific positions for their's position. so API look like GUI.Button(new Rect(...)) GUILayout uses automatic layout which means we don't need to specifiy positions for their's position. Layout logic will determine gui element's position automatically so API look like GUILayout.Button(...) What is difference between GUILayout and EditorLayout? Do not expect EditorLayout is a super set of GUILayout. Actually GUILayout and EditorLayout are totally different. Each classes has different kind of features so we can choose everything where it needs.