FULL PRODUCT VERSION :
java version "1.6.0-beta2"
Java(TM) SE Runtime Environment (build 1.6.0-beta2-b84)
Java HotSpot(TM) Client VM (build 1.6.0-beta2-b84, mixed mode, sharing)

A DESCRIPTION OF THE PROBLEM :
IntelliJ IDEA run with Mustang b84.
When closing the last editor I get:

0 >= 0
java.lang.ArrayIndexOutOfBoundsException: 0 >= 0
at java.util.Vector.elementAt(Vector.java:431)
at javax.swing.JTabbedPane.getComponentAt(JTabbedPane.java:1201)
at javax.swing.JTabbedPane.getSelectedComponent(JTabbedPane.java:637)
at com.intellij.ui.TabbedPaneWrapper
          ..........

Clearly getSelectedComponent() should return null when there are zro components, rather than crashing.

This is a regression since 5.0 release.


REPRODUCIBILITY :
This bug can be reproduced always.

Release Regression From : mustang
The above release value was the last known release where this
bug was known to work. Since then there has been a regression.