title: Qt - Password field, warn about Caps-Lock
body: <p>Is there any Qt-built-in method to warn user (with pop-up window) that CapsLock is switched on while password field is active?</p>
  
  <p>I am currently using <code>QLineEdit</code> (is it good?) with <code>setEchoMode(QLineEdit::Password)</code>.</p>