title: Can't change button GUIStyle background in EditorWindow
body: <p><em>Unity version: 2019.4.1f1</em></p>
  <p>I'm trying to change background of button in my EditorWindow. Trying to achieve effect pressed button in normal state:
  <a href="https://i.stack.imgur.com/yRFf1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yRFf1.png" alt="enter image description here" /></a></p>
  <pre><code>void OnGUI() {
       buttonStyleNormal = new GUIStyle(GUI.skin.button);
       buttonStyleToggled = new GUIStyle(GUI.skin.button);
       buttonStyleToggled.active.textColor = Color.blue;
       buttonStyleToggled.normal = buttonStyleToggled.active;
       ...
       GUILayout.Button(&quot;Developing&quot;, buttonStyleToggled);
       GUILayout.Button(&quot;Compilation&quot;, buttonStyleNormal);
   }
  </code></pre>
  <p>Result is here:<br />
  <a href="https://i.stack.imgur.com/6qmSN.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6qmSN.png" alt="enter image description here" /></a></p>
  <p>Problem stays even if I set background explicitly:</p>
  <pre><code> buttonStyleToggled.normal.background = buttonStyleToggled.active.background;
   buttonStyleToggled.normal.scaledBackgrounds = buttonStyleToggled.active.scaledBackgrounds;
  </code></pre>