Rename offline contact alias occur a NullPointerException in file ContactList.java:1123

Rename offline contact alias occur a NullPointerException in file ContactList.java:1123

Exception in thread “AWT-EventQueue-1” java.lang.NullPointerException
at org.jivesoftware.spark.ui.ContactList.actionPerformed(ContactList.java:1123)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)

is cause when offline users not grouped,

when offline users grouped together, alias can be renamed successful.