I have been spending various intermittent hours browser testing my latest Flex app recently, expecting there to be few, if any, differences between runing a Flex app on IE and on FireFox. I have also been doing Safari and Opera testing, though Flash player doesn’t 100% support them (chiefly, the Back button functionality doesn’t work, which is a bit of a pain in the ass).
One bug I found during IE testing was using relative URLs for uploading and downloading files was broken. I was using “../[folder]” to access a root folder (my flex app is inside a folder off the root) and whilst this worked on FireFox, when I went to IE 6 & 7 for testing, found it didn’t. Huh.