title: QLineEdit password obfuscation
body: <p>I am trying to implement a Login process with QT, and I'm curious about the safety of the <code>QLineEdit</code> widget. As I have seen online it seems that password remains stored even when <code>QLineEdit</code> is destroyed. Does overwriting with <code>QLineEdit::setText("mplampla");</code> solve the problem, or is the previous value kept somewhere?</p>