title: Eclipse Content Assist doesn't activate
body: <p>I can get an empty box to appear by pressing Ctrl Space, but content assist won't pop up at all otherwise. I've read lots of answers here on this topic but none have helped.</p>
  
  <p>I'm using...</p>
  
  <p>Ubuntu 12.10
  Eclipse Version: 3.8.0
  Build id: I20120502-2000
  Java openjdk-7-jre 7u15-2.3.7-0ubuntu1~12.10
  Execution Environment JavaSE-1.7 (java-6-openjdk)</p>
  
  <p>I've checked the Preferences settings and they seem reasonable.
  I've checked the project build settings and they look ok.
  I don't have any compile errors (and only a few lines of code.)</p>
  
  <p>Any suggestions as to what my next move is?</p>