title: Always not responding/freeze when use plot with QtOctave
body: <p>I'm new here.
  I've the same matter as <a href="https://stackoverflow.com/questions/12032494/octave-always-not-responding-freeze-when-use-plot">this one</a> but only using QtOctave; beside oct2mat pkg hasn't never been loaded on my pc.
  Typing:</p>
  
  <blockquote>
    <p>pkg unload oct2mat</p>
  </blockquote>
  
  <p>octave returns:</p>
  
  <blockquote>
    <p>error: package oct2mat is not installed
    error: \share\octave\3.6.2\m\pkg\pkg.m at line 2170, column 9</p>
  </blockquote>
  
  <p>Using plot function directly in Octave it works properly, very stange!</p>
  
  <p>Can enybody help me?
  Thanks in advance.</p>