May be incorrect QAbstractScrollArea::sizeHint() behavior.

Compile and run sample.cpp attached.

You will see main window with tableview inside. The tableview has small empty space just right of horizontal header. This is due to QAbstractScrollArea::sizeHint() implementation that takes into account virtual vertical scrollbar that can appear instead of that space.

The code is copy/pasted fragment of current implementation in Qt 5.14.0:

QSize QAbstractScrollArea::sizeHint() const
{
Q_D(const QAbstractScrollArea);
if (d->sizeAdjustPolicy == QAbstractScrollArea::AdjustIgnored)
return QSize(256, 192);

if (!d->sizeHint.isValid() || d->sizeAdjustPolicy == QAbstractScrollArea::AdjustToContents)

{ const int f = 2 * d->frameWidth; const QSize frame( f, f ); const bool vbarHidden = d->vbar->isHidden() || d->vbarpolicy == Qt::ScrollBarAlwaysOff; const bool hbarHidden = d->hbar->isHidden() || d->hbarpolicy == Qt::ScrollBarAlwaysOff; const QSize scrollbars(vbarHidden ? 0 : d->vbar->sizeHint().width(), hbarHidden ? 0 : d->hbar->sizeHint().height()); d->sizeHint = frame + scrollbars + viewportSizeHint(); }

return d->sizeHint;
}

 

Is this correct? Uncomment function CTableView::sizeHint() in attached sample.cpp, recompile and run again. You will see that empty space disappeared. Which behavior is more relevant?