title: Spring Tool Suite marks occurrences only after ten second delay
body: <p>I am running STS (Kepler/3.5.1.RELEASE) and experiencing an annoying issue in which Java editors will highlight occurrences of a variable/method/etc. only after a ten-second delay. </p>
  
  <p>This behavior seems to happen regardless of the following:</p>
  
  <ul>
  <li>number of validation types selected in the Mark Occurrences settings</li>
  <li>the number of project validators selected</li>
  <li>or the number of occurrence types I have selected</li>
  </ul>
  
  <p>A similarly sized Eclipse Juno installation on the same machine marks the occurrences almost instantaneously. Other editor types (e.g. Python) seem to highlight much more quickly, as I'd expect.</p>
  
  <p>Has anyone else seen this behavior?</p>