ok I’ve found a work around

<style>
.FlexColumn {display: flex;flex-flow: column nowrap }
.FlexColumn > div {display: inline-block; margin: -4px 0}
</style>

<div class="FlexColumn">
	<div>X</div>
	<div>X</div>
	<div>X</div>
	<div>X</div>
	<div>X</div>
</div>

But if someone have something more proper, I’m all ears.