How could I have missed that? FlashDevelop has better AS3 support now, including code completion.

I’ve already been using AS3 on it for a few days on a personal project of mine, but having that official patch helps. I can’t wait for a more final AS3 support though, as compiling is still a bit confusing (read, not supported out-of-the-box) and requires some additional installing/unzipping/XML editing.