Never too late to implement usability suggestions from 2003 :)
Pressing <tab> in konq's location bar is now much more useful: it completes the current path using the first (or current) item from the completionbox, and immediately offers the new completions (e.g. subdirs) again.

Other users of KLineEdit+KCompletionBox are not affected by default, since KCompletionBox still handles Tab/Shift+Tab as Down/Up by default [even though the apidox said this was off by default].