Look at the "View your posts" link relative to the "User Control Panel" link in the prosilver header nav, and you notice they are not vertically aligned the same.

The issue is that the iconized links use the class "small-icon" which has a top padding of 1px.

The non-iconized links, such as "View your posts" do not have the "small-icon" class, thus do not have the extra 1px of top padding, and so appear out of alignment by 1 pixel to the other nearby header nav links.