text: Q:
  
  Magento overriding a layout file causes the overriden layout to duplicate
  
  Okay, so I am trying to override a layout file of another extension. I am using Magento Enterprise 1.13
  This is my config.xml:
  <config>
      <frontend>
          <layout>
              <updates>
                  <mymodule>
                      <file>mymodule.xml</file>
                  </mymodule>
              </updates>
          </layout>
      </frontend>
  </config>
  
  Then in design/frontend/enterprise/mytheme/layout/mymodule.xml:
  <?xml version="1.0"?>
  <layout version="0.1.0">       
      <affiliateplus_default>
          <update handle="page_two_columns_left" />
          <reference name="left">
              <block type="affiliateplus/account_navigation" before="-" name="account_navigator" template="affiliateplus/navigation.phtml">
                  <action method="setNavigationTitle">
                      <title helper="affiliateplus/account/getNavigationLabel" />
                  </action>
                  <action method="addLink" translate="label" module="affiliateplus">
                      <name>balance</name>
                      <path>affiliateplus/inddsafdsex/paymentForm</path>
                      <label helper="affiliateplus/account/getBalanceLabel" />
                      <disabled helper="affiliateplus/account/accountNotLogin" />
                      <order>6</order>
                  </action>
                  <action method="addLink" translate="label" module="affiliateplus">
                      <name>home</name>
                      <path>affiliateplus</path>
                      <label>Affiliate Home</label>
                      <disabled>0</disabled>
                      <order>10</order>
                  </action>
                  <action method="addLink" translate="label" module="affiliateplus">
                      <name>login</name>
                      <path>affiliateplus/account/login</path>
                      <label>Login</label>
                      <disabled helper="affiliateplus/account/customerLoggedIn" />
                      <order>20</order>
                  </action>
                  <action method="addLink" translate="label" module="affiliateplus">
                      <name>register</name>
                      <path>affiliateplus/account/register</path>
                      <label>Signup</label>
                      <disabled helper="affiliateplus/account/isRegistered" />
                      <order>30</order>
                  </action>
                  <action method="addLink" translate="label" module="affiliateplus">
                      <name>banners</name>
                      <path>affiliateplus/banner/list</path>
                      <label><![CDATA[Banners & Links]]>
                      </label>
                      <disabled helper="affiliateplus/account/accountNotLogin" />
                      <order>40</order>
                  </action>
                  <action method="addLink" translate="label" module="affiliateplus">
                      <name>refers</name>
                      <path>affiliateplus/refer/index</path>
                      <label><![CDATA[Refer Friends]]>
                      </label>
                      <disabled helper="affiliateplus/account/accountNotLogin" />
                      <order>43</order>
                  </action>
                  <action method="addLink" translate="label" module="affiliateplus">
                      <name>materials</name>
                      <path>affiliateplus/index/materials</path>
                      <label>Materials</label>
                      <disabled helper="affiliateplus/config/disableMaterials" />
                      <order>100</order>
                  </action>
                  <action method="addLink" translate="label" module="affiliateplus">
                      <name>sales</name>
                      <path>affiliateplus/index/listTransaction</path>
                      <label>Commissions</label>
                      <disabled helper="affiliateplus/account/accountNotLogin" />
                      <order>110</order>
                  </action>
                  <action method="addLink" translate="label" module="affiliateplus">
                      <name>payments</name>
                      <path>affiliateplus/index/payments</path>
                      <label>Withdrawals</label>
                      <disabled helper="affiliateplus/account/accountNotLogin" />
                      <order>120</order>
                  </action>
                  <action method="addLink" translate="label" module="affiliateplus">
                      <name>referrers</name>
                      <path>affiliateplus/index/referrers</path>
                      <label>Traffics</label>
                      <disabled helper="affiliateplus/account/accountNotLogin" />
                      <order>180</order>
                  </action>
                  <action method="addLink" translate="label" module="affiliateplus">
                      <name>edit</name>
                      <path>affiliateplus/account/edit</path>
                      <label>Settings</label>
                      <disabled helper="affiliateplus/account/accountNotLogin" />
                      <order>190</order>
                  </action>
                  <action method="addLink" translate="label" module="affiliateplus">
                      <name>logout</name>
                      <path>affiliateplus/account/logout</path>
                      <label>Logout</label>
                      <disabled helper="affiliateplus/account/accountNotLogin" />
                      <order>200</order>
                  </action>
              </block>
          </reference>
      </affiliateplus_default>    
  </layout>
  
  However when I refresh the page I get TWO navigation panes. At first I thought I was just appending on to the one that was already there. However, when I make a change in mine it shows up in both of them. All I can think of is that it is pulling in my layout....then pulling in their layout and seeing my override and pulling in my layout again. Personally, this is the first time I have tried doing this so I very well could be doing it wrong but I can't find any help on this. Thanks for any help / comments.
  
  A:
  
  Well I found the answer:
  My REAL issue is that I did not know enough about references and blocks. 
  My TECHNICAL issue is that I was referencing one block and then creating a new block with a different name. The "Left" block also contained a version of the navigation bar. This was causing the duplicate menus. 
  My final code looks like this:
      <affiliateplus_default>
  
          <block type="affiliateplus/account_navigation" before="-" name="account_navigator" template="affiliateplus/navigation.phtml">
              <action method="setNavigationTitle">
                  <title helper="affiliateplus/account/getNavigationLabel" />
              </action>
              <action method="addLink" translate="label" module="affiliateplus">
                  <name>balance</name>
                  <path>affiliateplus/inddsafdsex/paymentForm</path>
                  <label helper="affiliateplus/account/getBalanceLabel" />
                  <disabled helper="affiliateplus/account/accountNotLogin" />
                  <order>6</order>
              </action>
  
              ......
  
      </affiliateplus_default>
  
  If I wanted to only add a link instead of completely overriding the entire block I could have done the following:
      <affiliateplus_default>
        <reference="account_navigator">
          <action method="addLink" translate="label" module="affiliateplusext">
              [Link attributes]
          </action>
        </reference>
      </affiliateplus_default>
  
  I hope this helps someone else that is just starting off. Thanks!
  
  