I think I've found a bug in Word 2010 when using styles with the Hidden font effect set.
Say I have a document with two custom styles: one a paragraph style and the other a character style, and they both have the Hidden font effect set to true. They look like this:
<w:style w:type="paragraph" w:customStyle="1" w:styleId="Style1">
<w:name w:val="Style1"/>
<w:basedOn w:val="Normal"/>
<w:qFormat/>
<w:rsid w:val="00800E6A"/>
<w:pPr>
<w:shd w:val="clear" w:color="auto" w:fill="FFFF00"/>
</w:pPr>
<w:rPr>
<w:vanish/>
<w:color w:val="FF0000"/>
</w:rPr>
</w:style>
<w:style w:type="character" w:customStyle="1" w:styleId="Style2">
<w:name w:val="Style2"/>
<w:basedOn w:val="DefaultParagraphFont"/>
<w:uiPriority w:val="1"/>
<w:qFormat/>
<w:rsid w:val="00800E6A"/>
<w:rPr>
<w:vanish/>
<w:color w:val="365F91" w:themeColor="accent1" w:themeShade="BF"/>
<w:bdr w:val="none" w:sz="0" w:space="0" w:color="auto"/>
<w:shd w:val="clear" w:color="auto" w:fill="D6E3BC" w:themeFill="accent3" w:themeFillTint="66"/>
</w:rPr>
</w:style>
If I apply the paragraph style to a paragraph and then apply the character style to a run of text within the paragraph, the hidden effect is turned off for this run of text, which means that if I print the document with the "Print hidden text" option set
to false the run of text with the character style applied appears in the print-out. The paragraph xml looks like this (note : I have cleaned up this xml for the purpose of this example):
<w:p>
<w:pPr>
<w:pStyle w:val="Style1"/>
</w:pPr>
<w:r>
<w:t>Test </w:t>
</w:r>
<w:r>
<w:rPr>
<w:rStyle w:val="Style2"/>
</w:rPr>
<w:t>test</w:t>
</w:r>
<w:r>
<w:t> test</w:t>
</w:r>
</w:p>
Would you consider this to be a bug?
Chris