Difference between F4_DXFILENAME and F4_DXFILENAME_TOPRECURSION'

Hi abappers,

I shearch the difference between F4_DXFILENAME and F4_DXFILENAME_TOPRECURSION,

Both are called for select file (local or server)?

In version ECC 6, F4_DXFILENAME_TOPRECURSION, is better?

Thanks for you attention.

Cordial greetings.