So I created a Catalyst project and uploaded the deploy to web folder to my web server. The first time I access the Main.html file - I can see in the bottom left of the browser - lots of downloading of files from adobe.com.After it runs that first time and I refresh, the page then it loads fine and quickly. The entire files is only 128k. It is only that initial load. I tried it from work, and the first time there - it also took a long time.
What is it loading that is taking so long and will this be the case with all catalyst files? OR should I be doing this differently?
Catalyst projects link to the Flex SDK using "runtime shared libraries". You can read more about RSLs elsewhere, but basically they make your SWF smaller, but the first time the swf is run it needs to pull down the RSLs.
I believe the RSLs are hosted on an Adobe server, and you can host them on your own server, too.
Once an RSL is downloaded, it remains in your Flash Player cache.
Since we are in beta, I'm not sure if the RSLs you are getting a production ones that stay in the cache or not, but from what you describe that seems to be the case. In any event, the production Flex RSLs will be cached always.
Also, note that this happens only once per Flex SDK version, globally for the user. So if someone has ever used a Flex 4-based app before, and then they visit your site, none of this downloading will occur since the signed Flex RSLs are already cached.