TYPO3 Core

Backend Modul "Page" shows strange behavior when trying to browse through the pagetree.
When expanding a folder, the pagetree is complete closing and it's not possible to load the page.

Since I've made a update from 3.5.0 to 3.7.0, the Page-Modul doesn't work. The admin-User isn't able to expanding the PageTree:
1. Mouseclick on "Page" loads the Page-Modul (fine)
2. Mouseclick on "+"-Sign in the Root opens the Pagetree and shows 3 Icons ("Template Storage", "Intranet", "Frontend Users").
3. Mouseclick on "+"-Sign on "Intranet" (PID 1) doesn't work. Instead of expanding the Tree, the PageTree is complete closing.

This error comes after choosing "Reset user preferences" (clear "uc" field).

When I login with other users, I'm always able to expanding the folder up to 2 levels. But when I try to open the next level, the complete Tree is closing again.

I've found the Bug-ID 0000758 with a similar bug, but I don't have the DAM-Extension installed.

This problem occurs only under HP-UX 11.0 (64-bit), the same installation works fine under Linux (32 bit). Is this a strange problem with PHP's serialize/unserialize-function (look at http://bugs.php.net/bug.php?id=31117)?
(issue imported from #M770)