When I was using flex I would run across strange bugs (such as invisible artifacts on the scrolling data grid which would make it so you couldn't trigger click/

When I was using flex I would run across strange bugs (such as invisible artifacts on the scrolling data grid which would make it so you couldn't trigger click/hover etc. events in random areas) which you are just "stuck with" as you can't exactly delve into the source and fix it yourself! I hate waiting for vendor updates! With extjs/yui etc. when I have come up against an oddity I have been able to get into the guts and figure it out (and usually figure out what I was doing wrong). Another factor would be accessibility. I know Extjs has this on their roadmap, what about flash/flex?