run SpreadSheet demo

/java/jdk/bin/jdkx -r 1.3 demo SpreadSheet

Click on a cell, then click on A, B, or C.
Exception thrown.

Exception occurred during event dispatching:
java.lang.ArrayIndexOutOfBoundsException: -1
        at SpreadSheet.mousePressed(SpreadSheet.java, Compiled Code)
        at java.awt.Component.processMouseEvent(Component.java, Compiled Code)
        at java.awt.Component.processEvent(Component.java, Compiled Code)
        at java.awt.Container.processEvent(Container.java, Compiled Code)
        at java.awt.Component.dispatchEventImpl(Component.java, Compiled Code)
        at java.awt.Container.dispatchEventImpl(Container.java, Compiled Code)
        at java.awt.Component.dispatchEvent(Component.java, Compiled Code)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java, Compiled Code)
        at java.awt.EventDispatchThread.pumpOneEvent(EventDispatchThread.java, Compiled Code)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java, Compiled Code)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java, Compiled Code)

Happens on both Windows and Solaris.

Discovered during AWT integration for kestrel-D.