Compare the bug file in Shumway extension version 0.9.2845 vs latest Flash Player. The text field's position is incorrect, vertically, by a few pixels. This is a base case. I have other test cases where the amount is greater. I can submit those if necessary.

Would be great if you could add one additional one so we can be sure it's one underlying reason (assuming it is).

I'm attaching another example that has extraneous stuff going on (and other problems). This has both a vertical and horizontal layout problem. For some reason, the files as staged live behave one way, whereas trying to recreate from scratch behave differently. So, use the staged URL to examine the behavior, and the files in the attachment to examine at your convenience. http://people.mozilla.org/~mwobensmith/flash/sandbox/parent.html

Fixed in https://github.com/mozilla/shumway/pull/1851.