title: Eclipse Ctrl+Space stopped working and a yellow rectangle shows up sometimes
body: <p>Every once in a while when I am coding in Eclipse, Ctrl + Space <strong>stops working</strong>. It just displays <strong>"No completions available"</strong> with red text in the bottom status-bar whenever I try.</p>
  
  <p>In addition to this, there is some strange code highlighting that can occur. I am not aware of why it happens, how it happens, or what it's purpose is. But I know how it looks (See screenshot)</p>
  
  <p><img src="https://i.stack.imgur.com/EsYL1.png" alt="Weird syntax highlighting in Eclipse"></p>
  
  <p>These problems are always related, whenever Ctrl + Space stops working, that weird highlighting has a tendency to show up. And whenever that shows up, I know that code completition is not working.</p>
  
  <p>I guess this mode is activated by me pressing some keyboard combination that I am unaware of.</p>
  
  <p>I believe this problem is not associated only with one type of project (for example Android or Swing).</p>
  
  <p><strong>How do I get rid of the Ctrl + Space problem and the weird highlighting without restarting Eclipse?</strong></p>