As scene has a .root added by default, then I think SB should be checking style sheets for .root declarations ?

i.e. If I attach a style sheet to my FXML with the following css...

.root {
    abc: red;
}

.button {
    -fx-background-color: abc;
}

...then SB should resolve the lookup without having to add the .root style class to the FXML (and Buttons in the FXML would have a red background).

This Jira comes from an issue posted by an SB user on the OTN forum and stackoverflow:
https://community.oracle.com/message/12491345
http://stackoverflow.com/questions/24167948/scenebuilder2-0-does-apply-rules-with-color-lookup