Calling "setSelected(true)" on CheckBox instance fires ActionEvent associated with this CheckBox. Example below prints "Triggered!". This behaviour was not present in JavaFX 2.2 (b4) and concerns only the first "setSelected(true)" call.

CheckBox checkBox = new CheckBox();
checkBox.setOnAction(new EventHandler<ActionEvent>() {
    @Override
    public void handle(ActionEvent event) {
        System.out.println("Triggered!");
    }
});
checkBox.setSelected(true);

EDIT: Also, suppressing implicit selection switch doesn't work. The following example causes stack overflow when CheckBox is clicked.

final CheckBox checkBox = new CheckBox();
checkBox.setOnAction(new EventHandler<ActionEvent>() {
    @Override
    public void handle(ActionEvent event) {
        checkBox.setSelected(!checkBox.isSelected());
    }
});