If you want to filter in a configure widget using a Hierarchical facet, you should use each level in the nested hierarchy that you want to add a filter for. If you have a hierarchical structure like this:
hierarchicalCategories.lvl0:"Cell phones"
hierarchicalCategories.lvl1:"Come with plans"
And you want to manually add a filter for "Come with plans" which is the child of Cell phones, then you should add filters for both attributes.
Although "hierarchicalCategories.lvl1:Come with plans" could be enough to get all the results you want, there might be other children with the same name as this. In that case we include the parent so that we can make sure we always get the expected result.