Also, unless you are doing something advanced with the WebView then the missing extension probably will not be an issue for you, and you can safely ignore the warning.
It is an issue for me, due to the fact that my application opens this warning in a popup every time I need wxWebView : I can’t ask my user to ignore this popup message each time it appears… It’s not convenient at all.
I hope you will find a way to fix that somehow, one day or another.
(meanwhile I have to stay with 4.0.6 version)