Are you trying to do this in the File Tab? I never use that area.
I don’t know about Windows but on Mac, you have the option to use the normal file selector pop up box and it works great. You can manually type or tweak path names, or use a normal menu system to navigate and do what needs to be done. This is one part of WaveLab where I never feel restricted or wanting better options so hopefully it’s just something simple on your end.