IM - Recipient sometimes sees black block instead of text when I use Windows 7 High Contrast theme

I use Lync client 2010 on 64 bit Windows 7. I like to use the Windows High Contrast Black theme. In Lync this sometimes causes an issue in that the person who I am sending messages to sees some of my messages as a black block/bar in their client (perhaps it could be black text on black background). In my client the message looks ok. Any ideas as to what I can do to resolve this would be appreciated as it is an inconvenience to have to switch to a non-high contrast theme every time I am having an IM conversation with someone.

Sincerely,

Daws