> Window managers have to maintain the same security guarantees (look at the trickiness behind the impersonation protection in Windows Vista's UAC for example),

> Window managers have to maintain the same security guarantees (look at the trickiness behind the impersonation protection in Windows Vista's UAC for example), and that's all the browser is in this context: a compositing window manager Browsers supply a lot more than that window management: menus, key event handling, find, scrollbars, etc. You don't have the ability to hook into these with enough flexibility, which is why Gmail has 1998-era pagination (which is still better than Yahoo Mail's janktastic infinite-scroll). The web simply doesn't let you show lots of email in a table like Mail.app, or even Google's native gmail app. > It's a common meme that "just reinvent the Web around applications and it'll be faster" Faster isn't really the point. Gmail is definitely not slow. Where it (and all web apps) fall short is in their lame UI, attempting to recreate desktop metaphors under the limitations of the web. Examples are its mystery meat keyboard shortcuts, almost-but-not-really context menus, its fixed-size non-draggable "windows" (chat, compose, etc).