I guess the situation becomes "good enough" when all the modern browsers include a hack to make scrolling work properly, but it's certainly not ideal. If anyone ever decides to write another browser they'll have to deal with another undocumented requirement, and there are funny cases to consider like transparent fixed headers.
Funny how frames are avoided for historical reasons when they often seem like the ideal solution. Remember when Twitter expanded conversations in a fixed box on the right of the screen? Should have used frames. Fixed header? Same deal.
If frames and iframes had been fixed instead of being ridiculed and discarded the web stack would be a better place.
Blogs wouldn't regularly collapse under load because blog posts could actually be static html pages instead of being dynamically generated just so we can slap the same header and linkroll on each one.
We wouldn't need new html5 tags to tell screen readers and crawlers where's the content and what's navigational elements because they would be in separate (i)frames.
Ajax's use could be actually reserved for interactive web applications instead of ugly optimizations like loading the comments separate from the article so the article itself loads faster.
I've been telling this to people for years, at my street corner, with my megaphone. But nobody is listening! It's a conspiracy!!!
Funny how frames are avoided for historical reasons when they often seem like the ideal solution. Remember when Twitter expanded conversations in a fixed box on the right of the screen? Should have used frames. Fixed header? Same deal.