OK, bummer, apparently Qt didn't think it a good idea to add a "size automatically but allow the user to change afterwards) :-(
There is QHeaderView::sectionSizeFromContents() but using that may give the same performance issue as your reverted fix (it's protected so you'd need to use a wrapped QHeaderView instance)? Is there a callback or event where you can query the size that Qt determined, set the resizemode to Interactive and then use resizeSection() with the obtained size value? I'll look at the sectionResized and geometriesChanged signals later. R.
