Custom Editor Window - GUI

using UnityEngine;
using UnityEditor;
using UnityEditor.SceneManagement;

public class BugReportWindow : EditorWindow {

    int normalTextSize;
    string windowTitle;
    Object source;
    int num = 0;

    [MenuItem("내가만든메뉴/내가만든윈도우")]
    static void Init()
    {
        BugReportWindow window = (BugReportWindow)EditorWindow.GetWindow(typeof(BugReportWindow));
        window.titleContent.text = "내가만든윈도우";        
        window.Show();
    }

    private void OnGUI()
    {
        GUILayout.BeginVertical();
        GUILayout.Space(10);
        GUILayout.BeginHorizontal();
        GUILayout.FlexibleSpace();
        normalTextSize = GUI.skin.label.fontSize;
        GUI.skin.label.fontSize = 25;
        GUILayout.Label("연습중");
        GUI.skin.label.fontSize = normalTextSize;
        GUILayout.FlexibleSpace();
        GUILayout.EndHorizontal();
        GUILayout.EndVertical();

        GUILayout.Space(10);
        windowTitle = EditorGUILayout.TextField("제목을 적어주세요", windowTitle, GUILayout.Width(300));
        GUILayout.Label("씬 : " + EditorSceneManager.GetActiveScene().path);
        GUILayout.Label("시간 : " + System.DateTime.Now.ToString());
        source = EditorGUILayout.ObjectField("오브젝트", source, typeof(Object), true);


        GUILayout.BeginHorizontal();
        GUILayout.Label(num.ToString());
        if (GUILayout.Button("+"))
            num++;

        if (GUILayout.Button("-"))
            num--;

        GUILayout.EndHorizontal();
    }
}