Bug: Upon boot, "kicker" loads and its background is visible. Details: Panels are set to "Hide Immediately" -- which they do -- though, unlike previous versions (3.4*), the panel does not re-appear when mouse cursor is placed over. Solution: This bug can be overcome by not utilising the "Hide Immediately" option, though this gives lesser usable screen space.
NO! This isn't a bug! It's a new feature! Good ol' KDE!