I noticed that only some ExtJS components/widgets use CSS sprites for the images and icons. But was wondering why hasn't this been implemented universally across all widgets and components.

The icons in the Tree component, for example, doesn't use sprites.

In IE6, where the browser only allows for up to 4 concurrent outbound connections per-domain, it takes a bit of time to download all the Tree icons (i.e. the folder and elbow icons). Implementing this using CSS Sprites would make loading quicker in this case.

I could easily implement this on my own using my own css file to override the default ExtJS css rules, however I would rather avoid this so that I don't have to keep on updating with each release (should the icons change).

My questions for the ExtJS dev team are:
  1. Are there any technical limitations or things to be aware of when implementing CSS Sprites for components such as the Tree?
  2. Will we see universal implementation of CSS Sprites across all/most ExtJS components in the future?