title: Trying to style pressed/selected style on MultiButton in Codename One results in Stack Overflow Error
body: <p>I just wanted to give a feedback to the user when they press a <code>MultiButton</code> that has been styled in CSS. </p>
  
  <p>The <code>MultiButton</code> is used like this :</p>
  
  <pre><code> String newStyleName = "NewText";
      Style newStyle = new Label("g", newStyleName).getUnselectedStyle();
      String newSubStyleName = "NewSubText";
      String newIconStyleName = "NewIcon";
  
  MultiButton nameButton = new MultiButton("Name");
      nameButton.setTextLine2("Give a name");
      nameButton.setIcon(FontImage.createMaterial(FontImage.MATERIAL_TEXT_FIELDS, newStyle));
      nameButton.setIconUIID(newIconStyleName);
      nameButton.setUIIDLine1(newStyleName);
      nameButton.setUIIDLine2(newSubStyleName);
      this.add(nameButton);
  </code></pre>
  
  <p>And styled like this :</p>
  
  <pre><code>NewText {
  color: #000000; 
  background-color: #e2f1f8;
  text-align: left;
  padding-left: 2mm;
  padding-right: 2mm;
  padding-top: 1mm;
  padding-bottom: 1px;
  margin-left: 0;
  margin-right: 0;
  margin-top: 0;
  margin-bottom: 0;
  font-family: "native:MainLight"; 
  font-size: 4.2mm; 
  }
  
  NewSubText {
  cn1-derive: NewText;
  padding-top: 0mm;
  padding-bottom: 1mm;
  margin-bottom: 0mm;
  color: #b0bec5;
  font-size: 3.5mm;
  }
  
  NewIcon {
  cn1-derive: NewText;
  padding-top: 1mm;
  padding-bottom: 1mm;
  padding-left: 2mm;
  padding-right: 2mm; 
  background-color: #e2f1f8;
  }
  </code></pre>
  
  <p>To achieve my goal to give feedback to the user, I have added :</p>
  
  <pre><code>NewText.pressed {
  cn1-derive: NewText;
  background-color: #808d94;
  }
  
  NewText.selected {
  cn1-derive: "NewText.pressed";   
  }
  </code></pre>
  
  <p>But this leads to an error in the simulator :</p>
  
  <pre><code>Error creating style NewText. selected: false prefix: press#[EDT] 0:1:2,42 - Error creating style NewText. selected: false prefix: press#
  
  java.lang.StackOverflowErrorjava.lang.StackOverflowError
  at com.codename1.io.Log.createWriter(Log.java:367)
  at com.codename1.io.Log.getWriter(Log.java:384)
  at com.codename1.io.Log.print(Log.java:348)
  at com.codename1.io.Log.p(Log.java:284)
  at com.codename1.io.Log.p(Log.java:274)
  at com.codename1.ui.plaf.UIManager.getComponentStyleImpl(UIManager.java:356)
  at com.codename1.ui.plaf.UIManager.createStyle(UIManager.java:1364)
  at com.codename1.ui.plaf.UIManager.getComponentStyleImpl(UIManager.java:349)
  at com.codename1.ui.plaf.UIManager.createStyle(UIManager.java:1364)
  </code></pre>
  
  <p>and if I keep pressing on the button it finally colors in the pressed background color. </p>
  
  <p>By the way if I only define the selected style (no pressed style) it does not compile :</p>
  
  <pre><code>java.lang.StackOverflowError
  at com.codename1.ui.css.CSSTheme$Element.getFlattenedStyle(CSSTheme.java:2650)
  </code></pre>
  
  <p>So it looks like there is a cyclic dependency problem between styles causing this stack overflow error but I cannot see where : <code>NewText</code> selector style is fully defined.</p>
  
  <p>What does this <code>false prefix press#</code> mean, and how can I do to remove this error ?</p>
  
  <p>Thanks in advance,</p>