- I'll look into the actual performance impact and provide measurements.
- X-browser: Yes, this is a problem, I agree. I think I can provide a simple shim for WebKitCSSMatrix. I just don't know yet when I will have time to get around to doing it.
- Moving $measureNode isn't an option really as the other CSS properties which are important wouldn't affect the node anymore. Here we would have to sync the properties which is even more expensive than the matrix operation, I think. It would also add complexity for event listeners and such.