cubicweb #5352619 can't remove entities linked through and inlined form when the relation is mandatory [validation pending]

we end up with 'relation is required' error message, while we would expect the composite relation to be removed.

priorityimportant
typebug
done in<not specified>
load1.000
load left0.000
closed by<not specified>
patch[inlined form] when some composite relation for an edited entity is removed, delete the entity [rejected]