Getting a Dropdown to Work in a Customised Excel Ribbon - excel

Question

So I'm creating a custom Ribbon using the Office RibbonX Editor and Excel. I want to display a simple dropdown that allows the user to switch between three worksheets.
I'm not sure why it's going wrong, but I keep running into three errors that correspond to the onAction attribute for each item:
Ln 8, Col 51: The 'onAction' attribute is not declared.
Ln 9, Col 51: The 'onAction' attribute is not declared.
Ln 10, Col 51: The 'onAction' attribute is not declared.
Here is my code:
XML (customUI14.xml file):
<customUI xmlns="http://schemas.microsoft.com/office/2009/07/customui">
<ribbon>
<tabs>
<tab id="customTab" label="DropDown" insertAfterMso="TabHome">
<group id="customGroup" label="Custom Group">
<dropDown id="dropDown1" label="Dropdown Box">
<item id="dd01" label="Sheet1" imageMso = "_1" onAction="DDOnAction" />
<item id="dd02" label="Sheet2" imageMso = "_2" onAction="DDOnAction" />
<item id="dd03" label="Sheet3" imageMso = "_3" onAction="DDOnAction" />
</dropDown>
</group>
</tab>
</tabs>
</ribbon>
</customUI>
VBA:
Sub DDOnAction(control As IRibbonControl, id As String, index As Integer)
Select Case control.id
Case "dd01"
ActiveWorkbook.Sheets("Sheet1").Activate
Case "dd02"
ActiveWorkbook.Sheets("Sheet2").Activate
Case "dd03"
ActiveWorkbook.Sheets("Sheet3").Activate
End Select
End Sub

Answer 1

Hi the onAction attribute should placed in the dropdown and not in the item,
So the XML is :
<customUI xmlns="http://schemas.microsoft.com/office/2009/07/customui">
<ribbon>
<tabs>
<tab id="customTab" label="DropDown" insertAfterMso="TabHome">
<group id="customGroup" label="Custom Group">
<dropDown id="dropDown1" label="Dropdown Box" onAction="DDOnAction" >
<item id="dd01" label="Sheet1" imageMso = "_1" />
<item id="dd02" label="Sheet2" imageMso = "_2" />
<item id="dd03" label="Sheet3" imageMso = "_3" />
</dropDown>
</group>
</tab>
</tabs>
</ribbon>
</customUI>
and the code is like this
Sub DDOnAction(control As IRibbonControl, id As String, Index As Integer)
Select Case Index
Case 0
ActiveWorkbook.Sheets("Sheet1").Activate
Case 1
ActiveWorkbook.Sheets("Sheet2").Activate
Case 2
ActiveWorkbook.Sheets("Sheet3").Activate
End Select
End Sub