XP being able to discover W10 computers on my private network

FYI, I never needed the Microsoft Service Advertising Protocol. The only time I installed a SAP was on Novell networks.
I'm still operating a network with 8 machines running Win10 (Enterprise, Pro and Home), Win7 (Ultimate and Pro), XP Pro, Win98 and even a (unnamed). The OP's issue is not unknown to me, but has always been resolved in the past.

@brucemc777: Meanwhile, you have an easy workaround. On the XP, map the Win10 drives (or folders) you need using FQDN (\\PUMBAA\...) if it's not already done.
When you'll be willing to run more tests, just tell me.

Indeed it's useless that window. He can map a drive, add a network resource or explore manually when he needs etc.

Much agreed. With a viable workaround I certainly do not wish to abuse you good folks! I'll just write off this puppy as solved.

Many thanks to all who tried to figure out what switch MS threw to mess up what once worked fine...