connect(ui->passwordSetLineEdit,SIGNAL(textEdited(QString)),this,SLOT(onTextEdit(QString)));

MyClass::MyClass() :
    edit(new QLineEdit(this))
{
    edit->installEventFilter(this);
}

bool MyClass::eventFilter(QObject* object, QEvent* event)
{
    if(object == edit && event->type() == QEvent::MouseClick) {
        // bring up your custom edit
        return false; // lets the event continue to the edit
    }
    return false;
}