PlacingContainers are introduced in this blog article: https://blog.mdriven.net/placingcontainers-flexbox/

Quick help for when you're confused by why you're seeing when working with placing containers (flex box)

Why isn't this container filling the one above it?

If you haven't made any special setting it's probably because a container only "fills" the container above in the perpendicular direction. If you want it to fill he whole width, for example for a table, make it's direction "Column".

• Direction Column => Fills horizontal and stacks vertical
• Direction Row => Fills vertical and stacks horizontal