TYPO3 Core

I just discovered a serious bug in using the checkbox "Stop page tree" inside the page properties.

Imagine this tree
Page 1
Page 2 <=== Stop page Tree
Sub 1
Sub 2
Sub 2.1
Sub 2.2
Sub 3
Page 3

If i want to see the pages inside "Page 2", i need to click at the red + which will then show only the pages below this so called temporary DB mount.

The problem is that it is not possible to set links to pages below the "Page 2" because in the popup of RTE I still see the complete page tree (and not the smaller tree as in the 2nd frame) and if I click the red icon there, nothing happens!

IMO there are 2 solutions:
- If i am inside a temp. DB mount, this should also be the tree in the popup (with an option to delete the temp DB mount there)
- If the tree is created inside the popup, no temp DB mount should be set.

Of course solution #1 is nicer but I guess needs also more time.

I tested with 4.2.4 and trunk
(issue imported from #M10224)