static void  ShowWindow()
        {
            SpriteSheetEditor window = EditorWindow.GetWindow <SpriteSheetEditor>(EditorPrefs.GetBool(typeof(SpriteSheetEditor).Name + "Detachable", false), "Create Sprite Sheet", true);

            window.minSize = new Vector2(windowWidth, 50);
            window.maxSize = new Vector2(windowWidth, 400);
            window.Repaint();
        }
        void OnGUI()
        {
            //Header
            GUILayout.BeginArea(new Rect(7, 0, this.position.width - 14, this.position.height));
            GUILayout.Space(5);
            GUILayout.Label("Create Sprite Sheet from Sequence", EditorStyles.boldLabel);
            EditorGUI.BeginChangeCheck();
            detachable = EditorGUILayout.Toggle("Detachable", detachable, GUILayout.Height(20));
            if (GUI.changed)
            {
                EditorPrefs.SetBool("detachable", detachable);
                this.Close();
                SpriteSheetEditor.ShowWindow();
            }
            if (GUILayout.Button("Choose Folder with Sequence", GUILayout.Height(25)))
            {
                folderpath = EditorUtility.OpenFolderPanel("Folder where PNG Sequence is located", getSelectedPath(), "");
            }

            GUILayout.Space(5);
            if (string.IsNullOrEmpty(folderpath))
            {
                EditorGUILayout.HelpBox("No folderpath given!", MessageType.Warning);
            }
            else
            {
                // just a little reminder that textures have to be advanced to be read (The Unity Exception thrown says pretty much the same thing but still)
                EditorGUILayout.HelpBox("Textures have to be Advanced & Read/Write has to be enabled! Texture Files have to be in PNG format.", MessageType.Info);
                xAxis = EditorGUILayout.IntField("#Sprites on X-Axis:", xAxis, GUILayout.Height(20));
                if (GUILayout.Button("Create Spritesheet", GUILayout.Height(25)))
                {
                    createSpriteSheetFromPNGSequence(folderpath);
                }
            }


            GUILayout.Space(5);
            //Resize window
            if (Event.current.type == EventType.Repaint)
            {
                Rect rect = GUILayoutUtility.GetLastRect();
                this.minSize = new Vector2(windowWidth, rect.y + 4);
                this.maxSize = new Vector2(windowWidth, rect.y + 4);
            }
            EditorGUI.EndChangeCheck();
            GUILayout.EndArea();
        }