Bug 67890 [PropertiesView] Exception when entries added to properties view
bundles/org.eclipse.ui.views/src/org/eclipse/ui/views/properties/PropertySheetViewer.java
PropertySheetCategory category = null;
        if (node instanceof IPropertySheetEntry)
            entry = (IPropertySheetEntry) node;
        else
            category = (PropertySheetCategory) node;
        boolean hasPlus = item.getItemCount() > 0;
        boolean needsPlus = category != null || entry.hasChildEntries();
        boolean removeAll = false;
        boolean addDummy = false;
        if (hasPlus != needsPlus) {
            if (needsPlus) {
                addDummy = true;
            } else {
                removeAll = true;
            }
        }
        if (removeAll) {
            
            TreeItem[] items = item.getItems();
            for (int i = 0; i < items.length; i++) {
                removeItem(items[i]);
            }
        }
        if (addDummy) {
            new TreeItem(item, SWT.NULL); 
            
        }
    }
}