Horizontal scroll bar doesn't show as needed when calling setWidgetResizable(true)

I have a QScrollArea, which contains a label that renders a html table. I called setWidgetResizable(true) to make sure the label stretches along with the scroll area but after I called this, the horizontal scroll bar doesn't show up as needed when the scroll area is narrower than the label.

The screenshot shows this issue: the scroll bar background is present but there is no scroll bar. The label thus can't be completely viewed in horizontal direction.

The issue can be easily reproduced when you set the minimum width of the label. I've uploaded a code snippet for you to inspect.