Bug 67890 [PropertiesView] Exception when entries added to properties view
bundles/org.eclipse.ui.views/src/org/eclipse/ui/views/properties/PropertySheetViewer.java
}
    /**
     * Asks the entry currently being edited to apply its current cell editor
     * value.
     */
    private void applyEditorValue() {
        TreeItem treeItem = treeEditor.getItem();
        
        if (treeItem == null || treeItem.isDisposed())
            return;
        IPropertySheetEntry entry = (IPropertySheetEntry) treeItem.getData();
        entry.applyEditorValue();
    }
    /**
     * Creates the child items for the given widget (item or tree). This
     * method is called when the item is expanded for the first time or when an
     * item is assigned as the root of the tree.
     * @param widget TreeItem or Tree to create the children in.
     */
    private void createChildren(Widget widget) {
        
        TreeItem[] childItems;
        if (widget == tree)
            childItems = tree.getItems();
        else {
            childItems = ((TreeItem) widget).getItems();
        }
        if (childItems.length > 0) {
            Object data = childItems[0].getData();
            if (data != null)