If you need to stylize your gui you can use the GUISettings class to change, the cursor color, flash speed, the selection color for text fields, as well as double click behavior.

    public class GuiSettingsExample : MonoBehaviour
    {
        public Color cursorColor;     
        public float flashSpeed;      
        public bool doubleClickSelectWord;       
        public Color selectionColor;             
        public bool tripleCLickLine;             
        private string text = "test string";     
        private Vector2 scroll;                  
        public GUISkin skin;                     

        public void OnGUI()
        {
            GUI.skin = this.skin;
            var settings = GUI.skin.settings;
            settings.cursorColor = this.cursorColor;
            settings.cursorFlashSpeed = this.flashSpeed;
            settings.doubleClickSelectsWord = this.doubleClickSelectWord;
            settings.selectionColor = this.selectionColor;
            settings.tripleClickSelectsLine = this.tripleCLickLine;


            this.scroll = GUILayout.BeginScrollView(this.scroll, false, false, GUILayout.ExpandWidth(true), GUILayout.ExpandHeight(true));
            this.text = GUILayout.TextArea(this.text);
            GUILayout.EndScrollView();
        }
    }