Maybe on 3.1.1 also...

• I have a "contact" page
• I create a "contact" page (nammed contact-2.html)
• I make it a forward page
• I select a root page "Sitemap"
• I click on "create a sub page"
• OK

The contact 2 page disapeared from left, but it still opened
The new page under sitemap is not visible (I have to close/open the sitemap to see it)
CTRL+SHIFT+F5 the contact-2 page is still missing
if I go in the properties of the newpage, I see contact-2 as referer of "new page"