Why if(pDrag->exec(Qt::MoveAction) == Qt::MoveAction) is nessesary for drag a item from QList?

[opengpu]

why
@
if(pDrag->exec(Qt::MoveAction) == Qt::MoveAction)
@

is nessesary for drag a item from QList?
@
if(pDrag->exec(Qt::MoveAction) == Qt::MoveAction)@

is at the last of ::startDrag()

if i delete this code, the drag effect will wrong, but i truly did nothing in the if
@
if(pDrag->exec(Qt::MoveAction) == Qt::MoveAction)
{
}
@

[edit: added missing coding tags @ SGaist]

[SGaist]

Hi

@
pDrag->exec(Qt::MoveAction)
@
Is the important part since it's there that the drag happens. However, since you are moving stuf, it means that on success you will remove the original data from it's container hense the if