Re-reading the first post in the linked forum thread, I believe that some of the issues he mentions, such as the up arrow not doing what's expected (in this case, providing a history like feature), are issues related to the behaviour of the console window in the sample, as opposed to some cegui lib related issue.
The issue of F12 not functioning as expected, is of course incorrect behaviour, and it is that type of issue that needs to be addressed when fixing this ticket.
Looking at the sample, it should indeed react to the up/down arrows - so those too form a valid part of the test.
user: Paul Turner <firstname.lastname@example.org>
date: Sat Feb 25 15:10:42 2012 +0000
summary: Fix: non-printable KeyDown events were always 'consumed' by editbox type widgets. This would cause issues where it is reasonable to expect non-handled key presses to propagate (like for example, in our own demo apps!).