Css, Js and <tr>

Why is it the simple css/xhtml code takes the longest problems to solve sometimes.I've been creating a table and for each table row there is a hidden row (<tr>) which spans the 13 columns. The idea is that when you click on the row the table expands to shows the hidden <tr> and pull in data via Ajax about that record. Initially i was using the following css to hide the rowdisplay:none;This is fine for IE and Firefox when it comes to hiding a table row but when you then apply "display:block" to bring the row back IE renders it fine, but Firefox doesnt quite get it right. This is because you need to use: display:table-rowI've test this in both IE 7 (beta) and FF and all seems fine, I will hopefully try this in some other browsers when I get back home.