Make child frames 100% width of parent when layout is vertical

Plugin and Widget API
1

Hello ! Please help.
I am making vertically-layouted frame with other frames (like display: flex, -flex-direction: column). I need children always to be 100% of width of parent !
Look at picture, I need grey ones to be full-width (even if there’s not enough content inside them, any way always fill (by width !))

image
image713×800 940 Bytes

So parentframe, of course, should have container.layoutMode = 'VERTICAL' . But what should I do further ?

2

How to set horizontal resizing to fill container on frame node - #2 by tank666.