solution for "Layout run failed" for 4.2.2 VBox / autoscroll / 100% width children

When upgrading from 4.2.0 to 4.2.2, part of our app failed to render with the error "Layout run failed". This a panel with a VBox layout, autoscroll, and child components with 100% widths. The layout worked by removing the autoscroll or the 100% widths, but to retain the same look the solution was to add "align: stretch" to the layout. I don't know if this is a bug because maybe we were doing it wrong all along, maybe the preferred/correct way of achieving this look is the stretch alignment. But I wanted to at least post it for others because it was completely obnoxious to track down. :)