a mistake when set backgroun-color value

i write these code :

-------------------------------------------------------------------------------------------------------------------------------------
HorizontalPanel hp=new HorizontalPanel();
Label lbl=new Label("aaaaa");
hp.add(lbl);
hp.setWidth("300px");
hp.setHeight("300px");
DOM.setStyleAttribute(hp.getElement(), "backgroun-color", "red");
DOM.setStyleAttribute(hp.getElement(), "border", "1px solid red");
RootPanel.get().add(hp);
-------------------------------------------------------------------------------------------------------------------------------------

then it wongs,the developement mod console said :
java.lang.AssertionError: The style name 'background-color' should be
in camelCase format

--
You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group.
To post to this group, send email to google-web-toolkit@googlegroups.com.
To unsubscribe from this group, send email to google-web-toolkit+unsubscribe@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.