NavigationPage + TabbedPage(more than 5 tab pages) issue on iOS.

I have an app with more than 5 tab pages, so the extra ones go under the "More..." tab on iOS.
There are 3 problems:
1. The top content is covered by the top menu on tab pages which are in the "More..." field.


2. The toolbar items on tab pages which are in the "More..." field are not visible when the first time it rendered.

3. The toolbar items on tab pages which are in the "More..." field are visible after visited the tab pages which are not in the "More..." field.