Hi
A Google search pointed me at two major GUI toolkits for Haskell: gtk2hs and wxHaskell.
My answer is to use Gtk2hs. Unfortunately, the releases are somewhat behind so you usually need to grab a special preview release to get it working on Windows. That's a very sad state of affairs, and as is easy to tell from this email, it gives the impression that Gtk2hs is busted on Windows. The *only* way to fix this is to have Gtk2hs builds go live within minutes of a GHC release going live - and I've been pushing for that for a while (but tend to give up once my computer is fixed...) Hopefully Duncan will know if your problem is due to using an old installer, or just a Vista thing - either way its a safe bet that Duncan will fix it in due course.
So, in practice, do other people write GUI apps with Haskell on Windows? And if they do, how do they do it? I feel I've got to the stage where I need a concrete recommendation from the experts.
Typically you need to use GHC and not GHCi - or at least you get more success that way. If the installation instructions for wxHaskell need improving, do tell the team behind it. wxHaskell was unmaintained for a while, so they are still picking up speed, getting the basics working - before tackling the polish issues. As a reference point, I still do all my GUI programming in C# - although am slowly taking pot shots at Haskell/Gtk2hs as new things crop up. Although I suspect I'm likely to try F# for GUI programming with my next project. Thanks Neil