ToolTip not disappear even hideText()

[stella1016]

I have a progressBar showing some progress by timer. If the progressBar doesn't change for 5sec, I will show the tooltip to give a hint. If the progressbar moves again, the tooltip should be hidden again. So, my tooltip is program-triggered.

The problem is that, when I hide the tooltip, it still shows.
I tried:

QToolTip::showText(this->mapToGlobal(progressBar_overall->pos()), "");
QToolTip::hideText();
QWidget::setToolTip("");

QToolTip::showText(this->mapToGlobal(progressBar_overall->pos()), "");
QToolTip::hideText();
QWidget::setToolTip("");

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All of these doesn't work for me. But if I do mouse-click of any widget inside the dialog of progressBar, the tooltip will disappear.

Anyone can help? Thanks.