title: Graphical Layout tab does not appear for some layout files into Eclipse
body: <p>I'm facing a problem when developing layout files for Android with Eclipse ADT Plugin. Some of my files, when opened, does not show the Graphical layout tab, just as below:</p>
  
  <p><img src="https://i.stack.imgur.com/C68DD.png" alt="enter image description here"></p>
  
  <p>The others (actually, the older ones), instead, show it correctly.</p>
  
  <p><img src="https://i.stack.imgur.com/ZM2uE.png" alt="enter image description here"></p>
  
  <p>Does anyone knows what can be done in this case?</p>
  
  <p>Thanks in advance!</p>