[TYPO3-core] rendermode = tree

[Robert Wildling]

Hi, dear core developer team,

After spending 2 weeks on the rendermode = tree issue i would like to 
report the following:

Google lists many unanswered questions when it comes to the 
###CURRENT_PID### filter possibility. After trying out thounds of times, 
I finally realized that it will only work when being within SysFolders, 
showing the one with the ###CURRENT_PID### as non-selectable.

This part of the documentation should IMHO be made much more clear and i 
wonder if I could help here.

The second thing about renderTree I would like to ask: is there any 
chance to make this feature work in more ways? It would be great if 
there is a possibility to really render only that part of the tree with 
the given pid - which is the big confusion at the moment with the 
###CURRENT_PID###, so it seems...

This could be helpful when presenting only a section of a tree to choose 
from (eg for a category system defined by pages that also need to be 
shown in the menu and therefore cannot be SysFolders).

Thanks!

Best regards,
Robert