I'm surprised that keyboard navigation in the tree would be relied on that heavily, and it hasn't come up before, but in the latest download (v6.2.0.6), the keyboard behavior of the tree control used in UR is now exposed via a registry setting (CharSearchMode), and defaults to matching on the next item down the tree (8 => CHARSEARCH_ALLCHARSWRAP2) before matching on items above the current item in the tree (3 => CHARSEARCH_ALLCHARS2).
See
https://www.kinook.com/Forum/showthread.php?t=5097 =>
CharSearchMode for more details.