Introduction
Layout
Most UI widgets are available in an auto layout version, and a version where the user manually sets a rect in whicht to draw the widget.
Auto layout widgets are in GUILayout.*
and EditorGUILayout.*
.
Manual layout widgets are in GUI.*
and EditorGUI.*
.
Styles
Editor styles are in UnityEditor.EditorStyles.*
, regular runtime styles are in GUI.skins.*
.
Be carefull not to change the default styles, as that would change all uses of that style, even the Unity editor itself. Always make a copy of a style that you cant to change, change the copy and use that copy.
var helpBoxStyle = new GUIStyle(EditorStyles.helpBox);
helpBoxStyle.normal.textColor = Color.blue;