title: The project XXX does not have any GWT SDKs on its build path
body: <p>Sometimes, when I start <em>Eclipse</em> (Java EE IDE for Web Developers, Indigo SR 1) on my <em>MacOSX Lion</em>, my <strong>GWT (2.4.0) project initially fails to compile</strong>.</p>
  
  <p>Eclipse displays the following message in the <em>"Problems"</em> section:</p>
  
  <pre><code>The project XXX does not have any GWT SDKs on its build path
  </code></pre>
  
  <p>Here is a list of semi-solutions that sometimes work (I normally try them in this order):</p>
  
  <ol>
  <li><code>Project &gt; Clean</code>.</li>
  <li>Remove and re-add GWT SDK to the build path.</li>
  <li>Restart the machine.</li>
  </ol>
  
  <p>Any help with preventing the problem from re-occurring would be most welcome.</p>