For whatever reason, Microsoft did not make Excel 2003/2007 Select-and-Say enabled. What you’re seeing is that every time WSR encounters a non-Select-and-Say enabled text window, it pops up the “dictation scratchpad”, which is WSR’s equivalent of Dragon’s dictation box. Unfortunately, that’s an issue that you have to take up with Microsoft. I haven’t tested in Microsoft Office 2010, but I wouldn’t be surprised with regard to Excel 2010 that the same issue arises. I will test it out and get back to you.
Nevertheless that’s why the dictation scratchpad is displayed whenever you’re in Excel 2007.