[KevinH]

That is up to DiapDealer since he is the Sigil Windows maintainer. Both Linux and macOS always use the non-native filedialogs since otherwise random crashing happened.

Perhaps he might be persuaded to add an environment variable to override what is there now but you would have to set it as preventing crashing is more important than speed for the majority of users.

But perhaps there is a better way that things can be speeded up? What exact type of networked drive are you using? Are you running Sigil from a networked drive as well?