when I have input focus on the desktop window and you type something I would expect the same behaviour as in dolphin file manager (which select the first file matching the text imput) instead it runs automatically the krunner.
If it is a wanted feature, it could be wise to let the user choose the desktop behaviour in a menu inside the system settings or leave such a behaviour to the cointainment.
This is currently desired behavior but you might have a point with your request.
i think it makes sense for the folderview containment to manage key events by itself (while the empty desktop containment would still fall back to the view launching krunner) could also make sense for the behavior to be changeable (only for folderview) in tweaks
*** This bug has been marked as a duplicate of bug 318538 ***