Forum Moderators: not2easy
You can display things based on hovering over a any element with css. It's not the easiest thing to code, and trying it on a <tr> is going to add to the complexity. But it can be done. This doesn't need a click, just pointing the mouse over the element is enough.
It's done using the psueudo-class :hover
IE6 will not support :hover on anything but a <a> tag, but you can easily find scripted help for IE6.
No time right now, but will post an example later.