Sitemap items are shown under "Documents" if a menuitem has internal link to "Page sitemapitem"

Steps to reproduce:

1. Create a new menu item.
2. Select internal link option and click on select button.
3. Add internal link to one of the Page sitemap items eg."experiments
4. Save it.
5. Now expand the same menu item
6. Click on select button to open picker
7. Notice "Documents" is selected in dropdown & page sitemap items are shown.In above case "experiments" is shown.

Expected:Related and relevant content should be shown for selected item in the dropdown on picker.

Check screenshot for reference.