1. Create a Site Template (myTemplate) with one page: page1
2. Create a subpage of page1: subpage1
3. Create a new "myTemplate" site (testSite)
4. Go to Admin Site (testSite) : Pages
5. Select the supage1 and try to add a subpage: subpagetest
Result: UI is broken, see attached image.
Expected: User can't add a subpage like this, currently subpages of pages linked to site template pages are not allowed.