Staffan, the thick lines behavior is the result of a missing initial table row. The top "blank" 1 pixel high row is left out of the community code (but found in the code I propose). This row is used by browsers to indirectly set the column width for other rows. It may seem odd to use this technique, but it works consistenty between browsers --it's not my idea, quite frankly. its standard practice used when slicing images. Without the initial blank table row, interpretation of html by browsers varies.
