XSD editor in netbeans IDE 6.8

Recently I downloaded netbeans IDE from http://netbeans.org/ everything seemed to be working fine until I tried to validate my .xsd file in it.
It showed me an error “Cannot find the declaration of element 'xsd:schema'.”  even though my xsd file was valid and began with xsd tag

 

<xsd:schema xmlns:xsd=http://www.w3.org/2001/XMLSchema
                     targetNamespace="http://www.example.org/schema/test/v1"
                     xmlns:tns="http://www.example.org/schema/test/v1" 
                     elementFormDefault="qualified"
                     version="1.0"> 
                     <!—ommitted –> 
</xsd:schema>

 

Finally I fixed this by downloading the XSD editor plugin from as follows

1) Open "Plugins" dialog from “Tools” menu
2) Go to "Settings" tab
3) Add an update center:
- Name: NetBeans Dev
- URL:
http://updates.netbeans.org/netbeans/updates/6.8/uc/m1/dev/catalog.xml.gz
4) Wait for catalog to be downloaded
5) Back to "Available plugins" tab
6) Intall plugin called "XML Schema and WSDL"

Finally I could edit XSD files and validate with Source , Schema and Design view.