Child Category Selection Not Working

I'm adding Galleries to single page blog posts and I'm unable to select a child category.
I have a category called auction-photos with child categories with unique names and I cannot get the sub category to remain selected. And I'm unable to see the full path showing the 2nd category ID.
There is no save button on the last selection screen (see screenshot) -- so I'm not sure how this is supposed to work.

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