Bug 182714 [Contributions] Improve toolbar configurability
bundles/org.eclipse.jface/src/org/eclipse/jface/action/CoolBarManager.java
}
            
            item = (IContributionItem) contributionList.get(contributionList
                    .size() - 1);
            if (item.isSeparator()) {
                contributionList.remove(contributionList.size() - 1);
            }
        }
        return contributionList;
    }
    /* (non-Javadoc)
     * @see org.eclipse.jface.action.ContributionManager#checkDuplication(org.eclipse.jface.action.IContributionItem)
     */
    protected boolean allowItem(IContributionItem itemToAdd) {
        /* We will allow as many null entries as they like, though there should
         * be none.
         */
        if (itemToAdd == null) {
            return true;
        }
        /* Null identifiers can be expected in generic contribution items.
         */
        String firstId = itemToAdd.getId();
        if (firstId == null) {
            return true;
        }
        
        IContributionItem[] currentItems = getItems();
        for (int i = 0; i < currentItems.length; i++) {
            IContributionItem currentItem = currentItems[i];