I realize this doesn't answer your OP but might just solve the issue regardless. Have you tried publishing for 10.2 to see if it solves the issue or does the same issue persis because the users computer may have FP11 installed anyhow? You should always be targeting the least version Flash Player necessary for the biggest compatibility demographic.

Do you have a public link where I can see this artifact in action?

5000px and transparent is asking for a LOT of trouble. While Flash tries to optimize by automatically only rendering redrawn regions, that is a huge amount of space. Just a browser rendering a transparent PNG at that size would be costly enough and bog the entire screen.

BTW you should never set something to 100%, the browser will continuously fight with the need for scrollbars. I realize you said you're going overflow:hidden; but previously you were 100%. You shouldn't do that, just a future note.

Also please keep in mind Browsers implement the majority of what you're doing, not Flash. The event chain hierarchy is pretty much in question here. You should be sizing your content in flash before you ever request the Flash plugin container to be resized. It looks like the resizing of the object happens before the data, but I can't be sure with your sample. A public sample would be much easier to diagnose.

Yes the stage should be set to NO_SCALE not NO_RESIZE (or if you did set it to NO_RESIZE, there's your issue).

Aside that I did take a 30fps screen recording of the content changing. Here's 6 frames from the movie.

Frame 1, selecting nav item.

Frame 2, squishing as you mentioned. How is the interface not updated before the resize request?

Frame 3, frame 4, frame 5, frame 6. These are not as you have been told to develop it. These should have been drawn and the layout completed before the resize but clearly the data is not in place before you resize. You need to go back and check your layout issue. You're not properly sensing when the layout of the new data is finished while resizing ahead of time.

Regardless if it worked in a previous version of Flash, the issue is with the order in which you're doing things. That or if you're using the invalid "NO_RESIZE" instead of "StageScaleMode.NO_SCALE".

Only on Webkit browsers. While I still see the order of your information (the one you're concerned with) is out of order, it works fine on Mozilla and IE. Webkit (Chrome/Safari) on Win are showing blinking. Chrome specifically shows the warping that you are experiencing, but Safari appears to only blink.

Here is a SCALED, 12fps example video of the scaling happening in 4 browsers open to approximately the limits you set, at the same time. You can see the Safari browser blink, sometimes to black. You can see Chrome blink, and sometimes warp like you're seeing. Mozilla and IE dutifully resize with no artifacting.

Typically if one browser engine has issues (e.g. WebKit) then all browsers with the same engine will also. That's why I brought up 2 to illustrate that (Safari/Chrome).

Example Video

I seriously doubt you'll be able to fix this without an extensive workaround involving screenshot foolery or (what I consider) unacceptable routes like 5000px documents to compensate.

You seem familiar with jQuery, why not just do it in HTML? There's nothing about the interface HTML/JS/CSS couldn't handle that I can see but I'm just looking at the front page.

Flash has a purpose that has simply changed. While it was perfectly possible to do most of what jQuery seems to make effortless before, nobody was willing to take on the mammoth task of browser differences with scripting. Only with the browser market conforming to standards is it becoming possible. Flash did fill that gap for a long time.

However that was never the main purpose of flash. Flash is about simple and/or sohpisticated animation, as spicy as you like. People using it for the wrong purposes doesn't mean it's Flash's fault any more than WebKits poor resizing of the Flash plugin is. It's WebKits fault, not Flash.

With 3D on the rise I feel Flash will finally debut as the preferred multimedia engine for upscale web content. The difference between HTML and Flash should be the difference between YouTube and IMAX. Point being, you should be able to tell the difference or else the author didn't use it for the right purposes.

You're welcome and if you're all set can you please mark it answered so we can filter unanswered questions and good luck!

I wish there was a simple answer but at least you can show your client it is a browser plugin rendering issue, not you.