EditorGUILayout.RectField
static function RectField(value: Rect, params options: GUILayoutOption[]): Rect;
static Rect RectField(Rect value, params GUILayoutOption[] options);
static def RectField(value as Rect, *options as GUILayoutOption[]) as Rect
static function RectField(label: string, value: Rect, params options: GUILayoutOption[]): Rect;
static Rect RectField(string label, Rect value, params GUILayoutOption[] options);
static def RectField(label as string, value as Rect, *options as GUILayoutOption[]) as Rect
static function RectField(label: GUIContent, value: Rect, params options: GUILayoutOption[]): Rect;
static Rect RectField(GUIContent label, Rect value, params GUILayoutOption[] options);
static def RectField(label as GUIContent, value as Rect, *options as GUILayoutOption[]) as Rect
Parameters

label Label to display above the field.
value The value to edit.
options An optional list of layout options that specify extra layouting properties. Any values passed in here will override settings defined by the style.
See Also: GUILayout.Width, GUILayout.Height, GUILayout.MinWidth, GUILayout.MaxWidth, GUILayout.MinHeight, GUILayout.MaxHeight, GUILayout.ExpandWidth, GUILayout.ExpandHeight.
Returns
Rect The value entered by the user.
Description

Make an X, Y, W & H field for entering a Rect.


''Modify Another's window position and size values.''
	// Simple Script that lets you modify another's window position value
	//
	// To use this script you need to open first the DummyWindow window.
	
	class MoveResizeSelectedWindow extends EditorWindow {
	
		var pos : Rect;
	
		@MenuItem("Examples/Move - Resize other window")
		static function Init() {
			var window = GetWindow(MoveResizeSelectedWindow);
			window.Show();
		}
		
		function OnGUI() {
			DummyWindow.instance.position = 
				EditorGUILayout.RectField("Window's position:", 
											DummyWindow.instance.position);
			if(GUILayout.Button("Reset position"))
				DummyWindow.instance.position = Rect(0,0,200,200);	
			if(GUILayout.Button("Close"))
				this.Close();
		}
	}
And the script that works with the example:
	// Dummy window that is going to be moved.
	
	class DummyWindow extends EditorWindow {
	
		static var instance;
		@MenuItem("Examples/Dummy Window")
		static function Init() {
			var window = GetWindow(DummyWindow);
			window.Show();
		}
		function DummyWindow() {
			instance = this;
		}
	}