Cannot open wsxz package

A couple of days ago, I installed Studio 2021. I have received a wsxz package which I cannot open because the known *.sdlppx, *.wsxz, ... configuration for "all files" does nor show, but only *.sdlppx, *.sdlrpx shows. There is not any problem with Studio 2019 which I checked to compare. In Studio 2021, when opening the package concerned, the msg. ,however, also states "all files" but is limited to *.sdlppx, *.sdlrpx - and that's it. Is there a bug or due to using WIN 7 as O/S. I would very much appreciate your early advice. It is a bit disappointing that this issue has emerged.