Hello, in the app designer version 2019a, the auto-reflow does not work, the children objects do not resize even if I check the autoresizechildren check box. I have a colleague who has the same issue. Thanks!
Auto-reflow is different than the autoresize option. Autoresize will resize components for you when the window is resized. Reflow is only possible if you build an app using the new reflow template. This will not only resize your content but also reflow it.