Bug 56818 [PropertiesView] Clicking on Advanced Properties toggle when categories are collapsed removes the + next to the category
Clicking on Advanced Properties toggle when categories are collapsed removes the plus sign (+) next to the category and it can no longer be expanded. To reproduce: 1.)Open the Properties view. 2.)Have Show Categories turned on, and Show Advanced Properties turned off. 3.)Collapse all open categories. 4.)Click the Show Advanced Properties button. 5.)Note the plus sign goes away and the categories can no longer be expanded. You need to click the Show Advanced Properties button off to see the plus sign again.
bundles/org.eclipse.ui.views/src/org/eclipse/ui/views/properties/PropertySheetViewer.java
* @return the children of the given category or entry
	 *  (element type <code>IPropertySheetEntry</code> or 
	 *  <code>PropertySheetCategory</code>)
	 */
	private List getChildren(Object node) {
		
		IPropertySheetEntry entry = null;
		PropertySheetCategory category = null;
		if (node instanceof IPropertySheetEntry)
			entry = (IPropertySheetEntry) node;
		else
			category = (PropertySheetCategory) node;
		
		List children;
		if (category == null)
			children = getChildren(entry);
		else
			children = getChildren(category);
		return children;
	}
	/**
	 * Returns the child entries of the given entry
	 * 
	 * @return the children of the given entry (element type
	 *         <code>IPropertySheetEntry</code>)
	 */
	private List getChildren(IPropertySheetEntry entry) {