Trouble understanding Events (need help- simple question though)

Unity Engine
1

Howdy there! Can anyone explain to me why this EditorWindow doesn’t draw a GUI.Box when the mouse is clicked/down? Much appreciated if anyone has time, thanks!

using UnityEngine;
using UnityEditor;
using System.Collections;

public class TestEditorWindow : EditorWindow {
	
	[MenuItem("Window/TestEditorWindow")]
	static void Init () {
        TestEditorWindow window = (TestEditorWindow)EditorWindow.GetWindow(typeof(TestEditorWindow));
		window.Show();
    }
	
	void OnGUI() {
		if(Event.current.isMouse) {
			GUI.Box(new Rect(10, 10, 10, 10), GUIContent.none);
		}
	}
}
2

As far as I can tell, it’s that you don’t get mouse events if the mouse is being held(i.e down, but not dragged).

if(Event.current.button == 0  Event.current.isMouse) //do stuff here that you want done if the left button is held down