SetOpacity() in Firefox 3.1 Beta 2

What steps will reproduce the problem?
Just an example code:

        Canvas transparent = new Canvas();
        transparent.setWidth100();
        transparent.setHeight100();
        transparent.setBackgroundColor("#555");
        transparent.setOpacity(30);

What is the expected output? What do you see instead?
the error given is:
----------------------------------------------------------------
Warning: Unknown property '-moz-opacity'.  Declaration dropped.
Source File:
http://localhost:8888/pt.gedi.base.interfaceClient.EntryPoint/EntryPoint.html
Line: 0
----------------------------------------------------------------

What version of the product are you using? On what operating system?
windows xp, gwt 1.5.3, smartgwt revision 226, firefox 3.1beta2

Please provide any additional information below.
in firefox 3.0 is working.
It seems that from 3.1 now the name is only "opacity"
From their site: "Remove support for the deprecated -moz-opacity in favor
of opacity " source:
https://developer.mozilla.org/en/Firefox_3.1_for_developers

Original issue reported on code.google.com by mihai.ile@gmail.com on 16 Jan 2009 at 3:54

omradouane / smartgwt

SetOpacity() in Firefox 3.1 Beta 2 #84