Custom UI elements using add-ins
Config.esriaddinx
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<ESRI.Configuration xmlns="http://schemas.esri.com/Desktop/AddIns" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Name>Dharama</Name>
  <AddInID>{438eb6a9-8b23-49e3-8385-d49d306aa94d}</AddInID>
  <Description>A custom collection of mapping tools for Dharma Initiative personnel.</Description>
  <Version>1.0</Version>
  <Image>Images\CustomUIElements.png</Image>
  <Author>John Locke</Author>
  <Company>Dharma Inst.</Company>
  <Date>9/18/2009</Date>
  <Targets>
    <Target name="Desktop" version="10.1" />
  </Targets>
  <AddIn language="CLR" library="CustomUIElements.dll" namespace="CustomUIElements">
    <ArcMap>
      <Commands>
        <Tool id="ESRI_CustomUIElements_AddGraphicsTool" class="AddGraphicsTool" 
              tip="Digitize a line" message="Digitize a line" 
              caption="Add Graphics Tool" 
              category="Add-In Controls" image="Images\AddGraphicsTool.png">
          <Help heading="Add Graphics Tool">Digitize a line on a map.</Help>
        </Tool>
        <Button id="ESRI_CustomUIElements_ZoomToLayerButton" class="ZoomToLayerButton" 
                tip="Zoom to selected layer" message="Zoom to selected layer." 
                caption="Zoom To Layer" category="Add-In Controls" 
                image="Images\ZoomToLayerButton.png">
          <Help heading="Zoom To Selected Layer">Sets the extent to the selected layer.</Help>
        </Button>
      </Commands>

      <Menus>
        <Menu id="ESRI_CustomUIElements_UIMenu" caption="Zoom Commands" isRootMenu="true" isShortcutMenu="true">
          <Items>
            <Button refID="esriArcMapUI.FullExtentCommand" />
            <!--Sub Menus-->
            <!--ArcGIS Built-in Menu-->
            <Menu refID="esriArcMapUI.MxZoomLayoutMenu" />
            <!--Custom Menu-->
            <Menu refID="ESRI_CustomUIElements_UISubMenu" />
          </Items>
        </Menu>
        <Menu id="ESRI_CustomUIElements_UISubMenu" caption="More Zoom Commands">
          <Items>
            <Button refID="esriArcMapUI.ZoomToLastExtentBackCommand" />
            <Button refID="esriArcMapUI.ZoomToLastExtentForwardCommand" />
          </Items>
        </Menu>
      </Menus>

      <Toolbars>
        <Toolbar id="ESRI_CustomUIElements_UIToolbar" caption="Dharma Toolbar">
          <Items>
            <Tool refID="ESRI_CustomUIElements_AddGraphicsTool" />
            <Button refID="ESRI_CustomUIElements_ZoomToLayerButton" />
            <!--ArcGIS built-in Commands-->
            <!--Fixed Zoom In; refID can be ProgID-->
            <Button refID="esriArcMapUI.ZoomInFixedCommand" />
            <!--Fixed Zoom out Command; refID can be GUID-->
            <Button refID="{0830FB34-7EE6-11D0-87EC-080009EC732A}" />
            <!--ArcGIS built-in Menus-->
            <Menu refID="esriArcMapUI.MxZoomLayoutMenu" />
          </Items>
        </Toolbar>
      </Toolbars>
    </ArcMap>
  </AddIn>
</ESRI.Configuration>