You cannot paste text enclosed in HTML tags from a web browser to a Lync 2010 conversation window
Content provided by Microsoft
Applies to: Lync 2010
Assume that you use a web browser to open an .html file that contains <fieldset> tags. In this situation, you cannot paste the text that is contained within the <fieldset> tags into a Microsoft Lync 2010 conversation window.
To resolve this issue, install the following cumulative update:
2701664 Description of the cumulative update package for Lync 2010: June 2012