XML not Validating

[KenKrugh]

Should start by saying this is a FABULOUS tool, and thank you! This issue could be my lack of knowledge of VS2012 so please bear with me.

When editing a Word template (dotm file) the XML doesn't seem to be validating. A case in point is a duplicate id attribute value on 2 different buttons. While editing the XML in the package VS doesn't flag that as a problem.

But, if I create a new XML file in VS and copy and paste the entirety of my customUI.xml file VS flags that problem, even though it's all the exact same code.

Is there something I need to do in VS to get the validation working when editing the package?

Thanks again!
Ken