I have a Spark list with a customItemRenderer that is taking a good 3 seconds to initialize with just 50 items.
I'm using Flex 4.5, my ItemRenderer is already very optimized, using as little nesting as possible, fxg and so on.
Is anyone having similar issues? I've tried almost everything in the book bar going back to mx.
Are your item renderers checkboxes by any chance? A few folks have recently run into a bunch of performance issues with Spark in general.
Adobe has been notified, and apparently are working on it: https://bugs.adobe.com/jira/browse/SDK-29451