After my program executes (correctly) I see a long list of error messages. These do not reflect a serious problem, apparently (since the program runs OK) but they are annoying and I'd like to get rid of them.
All the messages look like this:
Object::connect: No such signal QLabel::labelClicked(QString)
Object::connect: (sender name: 'label_hour')
Object::connect: (receiver name: 'MainWindow')

with variations of sender name.

I have extended QLabel to QMyLabel thus:

#ifndef QMYLABEL_H
#define QMYLABEL_H

#include <qlabel.h>
class QMyLabel: public QLabel
{
Q_OBJECT
public:
QMyLabel(QWidget *parent = 0);
signals:
void labelClicked(QString text);
private:
void mousePressEvent (QMouseEvent *event);
};

#endif

and

QMyLabel::QMyLabel(QWidget *parent) : QLabel(parent)
{}

//------------------------------------------------------------------------------------------------------------------
// Redefines mousePressEvent for QMyLabel, which extends QLabel. This is used to display info about a model parameter.
//------------------------------------------------------------------------------------------------------------------
void QMyLabel::mousePressEvent (QMouseEvent *event) {
event->accept();
QString sname = objectName().mid(6);
QString text = "mousePressEvent";
// Find which label_ sent the signal, and read its text
for (int k=0; k<parm->nParams; k++) {
PARAM_SET param = parm->get_param(k);
if (sname.compare(param.tag) == 0)
text = param.text;
}
emit labelClicked(text);
}

In Qt Creator I promote many QLabels to QMyLabel in order to display info about the fields they label.

Why does this trigger error messages when the program executes?