Visual Studio Designer: Opening XML files as a Grid (hidden feature)

I once had this Add-In to VS2005 that allowed me to edit XML files in a Excel-Like table view. I would access it by right-clicking an XML file from within Visual Studio, click Open With, and then select the Add-In. I would then be able to read/write my simple XML in a nice table format.

The way I remember it, this feature was shipped with VS2005 but never actually got registered with the "Open With" dialog box, although the necessary DLL was resident on the machine (shipped with VS2005)

Does anyone know what this DLL is called? I first learned of this secret feature from a blog post I have long lost, and am fairly certain I didn't install any 3rd party software to make this file av开发者_StackOverflow社区ailable to me.

It may be possible that this addin to the VS Designer still exists in 2008, or 2010... but after searching for this feature for 3 years, I'm just doing a sanity check now.

Edit:

And as an added bonus, the DataSet object was able to read /write this XML format with no special parsing or formatting required

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I remember that feature too - but it looks like it was removed:

http://social.msdn.microsoft.com/Forums/en-US/xmlandnetfx/thread/a739d5e7-b42c-4250-904d-e43e731ba784