Exposed taxonomy filter ignores hierarchy

When we have hierarchy like:

- A
-- 1
-- 2
-- 3

And nodes :
node1 - assigned term 1
node2 - assigned term 2

The expected behavior for selecting "A" in taxonomy filter on views is to display every node assigned to A,1,2 or 3. In this case displaying 2 nodes.

But the current behavior ignores that hierarchy and displays only those assigned to "A". No child-terms taken into account.