FULL PRODUCT VERSION :


A DESCRIPTION OF THE PROBLEM :
when I use a JRadioButton with a ButtonGroup, and add it to JInternalFrame, then press the keyboard: <tab> cannot transfer focus to next componentUI, and in log.txt you can see the exception stack.
But when I add the JRadioButton in a JDialog, without this problem at all.

REGRESSION. Last worked in version 8u45


ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: aContainer is not a focus cycle root of aComponent
at javax.swing.SortingFocusTraversalPolicy.getComponentAfter(SortingFocusTraversalPolicy.java:305)
at javax.swing.LayoutFocusTraversalPolicy.getComponentAfter(LayoutFocusTraversalPolicy.java:106)

REPRODUCIBILITY :
This bug can be reproduced always.