[Petr] - whole "Source" tab was removed.

If window "Property Editor: Package (String)" is opened for some class in tab Source to see package, the following exception is thrown and then if OK button is pressed IDE hangs. Pressing Cancel buton
 sometimes opens window with message "exception in setter method of property: Package".
This exception is written only to netbeans.log file.

java.lang.IllegalArgumentException
        at java.lang.Throwable.fillInStackTrace(Native Method)
        at java.lang.Throwable.fillInStackTrace(Compiled Code)
        at java.lang.Throwable.<init>(Compiled Code)
        at java.lang.Exception.<init>(Compiled Code)
        at java.lang.RuntimeException.<init>(RuntimeException.java:37)
        at java.lang.IllegalArgumentException.<init>(IllegalArgumentException.java:33)
        at com.netbeans.developer.modules.loaders.java.JavaNode$2.setValue(JavaNode.java:147)

        at com.netbeans.ide.explorer.propertysheet.PropertyDetails.setPropertyValues(Compiled Code)
        at com.netbeans.ide.explorer.propertysheet.PropertyDialogManager.cancelValue(PropertyDialogManager.java:198)
        at com.netbeans.ide.explorer.propertysheet.PropertyDialogManager.doButtonPressed(PropertyDialogManager.java:212)
        at com.netbeans.ide.explorer.propertysheet.PropertyDialogManager.access$0(PropertyDialogManager.java:209)
        at com.netbeans.ide.explorer.propertysheet.PropertyDialogManager$1.actionPerformed(PropertyDialogManager.java:141)
...