It is now possible to change the Access File in the page settings, which is very useful with umlauts as nobody really wants them to be converted to something like ae and oe in the URL. However, new subpages will have their parent page's menu title included in the URL's path instead of the defined Access File of the parent. This is especially frustrating when the parent page's menu title has umlauts and one wants to get rid of all ae's an ao's in the URL.
Here is an example:
Page title: Äölk
Menu title: Äölk
Parent: None
Access file: aolk
URL --> /pages/aolk.php

Now create a new subpage with Äölk as parent:
Page title: Subpage
Menu title: Subpage
Parent: Äölk
Access File: subpage
URL --> /pages/aeoelk/subpage.php

There is a dirty workaround if you go to Subpage's settings and just hit Save, the URL changes to /pages/aolk/subpage.php as was wanted in the beginning. This will, however, leave an unused folder "aeoelk" in the pages directory.
Btw, CANCEL button does not work in the page settings..