Shared Tabs

It is possible to share a custom ribbom between files.
One file might create a custom tab and add a group of controls.
Another file could then add a second group of controls to the same tab.

xmlns:BSN

Add an additional namespace to the <customui> tag.
This allows us to link each XML namespace between different files and add-ins.
It must be the same in each file that is going to share the custom ribbon tab.

<?xml version="1.0" encoding="UTF-8"?> 
<customUI xmlns="http://schemas.microsoft.com/office/2009/07/customui"> 
          xmlns:BSN="Namespace"> 

tab idQ

Use the "idQ" instead of the "id".
This refers to our qualified namespace and gives us a way to create a shared tab that can be accessed from other files.

      <tabs> 
        <tab idQ="BSN:BetterSolutions" 
             label="My Custom Tab"> 
          <group>