Nimbus: JTabbedPane setBackgroundAt and setForegroundAt have no effect

Tests api/javax_swing/interactive/JTabbedPaneTests.html#JTabbedPane[JTabbedPaneTest0007] and api/javax_swing/interactive/JTabbedPaneTests.html#JTabbedPane[JTabbedPaneTest0008] fail with Nimbus LaF. Tests check setBackgroundAt and setForegroundAt methods of the class JTabbedPane . Without Nimbus LaF test changes font and background of tabs. With Nimbus it has no effect.

steps to reproduce:

change path to JCK 6b and run

set CLASSPATH=C:\\JCK\\JCK-runtime-6b\\classes;C:\\jcktest\\JCK-runtime-6b\\lib\\javatest
C:\\JDK\\jdk1.6.0_10\\bin\\java.exe -Dswing.defaultlaf=com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel -Djava.security.policy=C:\\JCK\\JCK-runtime-6b\\lib\\jck.policy javasoft.sqe.tests.api.javax.swing.interactive.JTabbedPane.JTabbedPaneTests -TestCaseID JTabbedPaneTest0007 -TestDirURL file:/C:/jcktest/JCK-runtime-6b/tests/api/javax_swing/interactive/JTabbedPaneTests.html#JTabbedPane