If you start from scratch, then using the getVisible attribute to show/hide a tab will not work, since you'd have to rebuild the functionalities for the elements. However, an option would be to simply start all tabs hidden and then show/hide as you go along, this would avoid the frustrating of having to rebuild each tab using XML to work with them.

Remember that working with startFromScratch does not stop the user from hitting shortcut keys to access certain functionalities (at least for now), so it is pretty much pointless to start from scratch except for the fact you’d have all the tabs and certain commands hidden from the outset. Here’s an option to work with an Excel file. Use the following XML to built your own custom tab:

<customUI
  xmlns="http://schemas.microsoft.com/office/2006/01/customui"
  onLoad="rxRibbon_onLoad">

  <ribbon
   startFromScratch="false">
   <tabs>
    <tab
     idMso="TabHome"
     getVisible="TabHome_getVisible"/>
   <tab
     id="rxTab0"
     label="My Custom Tab">

     <group
      id="rxGrp0"
      label="My Custom Group">

      <toggleButton
       id="rxtglBtn0" getLabel="rxtglBtn0_getLabel"
       imageMso="HappyFace"
       size="large"
       onAction="rxtglBtn0_Click" />
     </group>
    </tab>
   </tabs>
  </ribbon>
</customUI>

Public rx_oRibbon             As IRibbonUI
Public blnGetLabelState       As Boolean
Public blnHomeTabVisibility   As Boolean

Sub rxRibbon_onLoad(ribbon As IRibbonUI)
  Set rx_oRibbon = ribbon
  blnGetLabelState = False
  blnHomeTabVisibility = False
End Sub

Sub rxtglBtn0_getLabel(control As IRibbonControl, ByRef returnedVal)
  Select Case blnGetLabelState
    Case True
      returnedVal = "Hide 'Home Tab'"
    Case False
      returnedVal = "Show 'Home Tab'"
  End Select
End Sub

Sub TabHome_getVisible(control As IRibbonControl, ByRef returnedVal)
  returnedVal = (blnGetLabelState)
End Sub

Sub rxtglBtn0_Click(control As IRibbonControl, pressed As Boolean)
  blnGetLabelState = pressed
  rx_oRibbon.Invalidate
End Sub