Why cant I scroll Horizontally in GUI.BeginScrollArea when i set GUIStyle params to null ?

Here is an example

I want my scroll area without any scrollbars . Unity gives us this option.

However when I implement it . I can only scroll virtically with my trackpad or graphics tablet ... but I cant scroll horizontally here :

 public Vector2 ScrollView;
 
 void OnGUI()
 {
  ScrollView = GUI.BeginScrollView(new Rect(0, 0,300,100), ScrollView, new Rect(0, 0, 900,100), GUIStyle.none, GUIStyle.none);
 
 //I can still scroll birtically
 //but
 // I cant scroll Horizontally here  
 
 GUI.EndScrollView();
 
 }