title: qDebug not displaying anything
body: <p>Often when I need to debug something it's easier to print something using <code>qDebug()</code> instead of debugging step-by-step using a debugger. 
  The problem is that from time to time the output of <code>qDebug()</code> isn't displayed at all! The same with <code>qWarning</code> and <code>qCritical</code>. What's strange, it only occurs when running the project normally (Ctrl+R), while when debugging (F5) the output shows up.</p>