CLONE -QTreeWidget: setResizeMode(QHeaderView::ResizeToContents) unacceptably slow

Steps to reproduce / test case:

When setResizeMode(QHeaderView::ResizeToContents) is selected in QTreeWidget, all operations become unacceptably slow.

Please compare the following results:

With:
setColumnWidth( 0, 10240 );
setResizeMode(QHeaderView::Stretch);
my application takes ~200 miliseconds to create and render a large view with ~1000 items.

With
setResizeMode(QHeaderView::ResizeToContents)
the same takes over 6 seconds.

I.e. with ResizeToContents 30-times more CPU time is needed to create the same view.