A box that appears when we hover a mouse over any forum-threads and it shows the first post of that

As the subject says, I want a box that appears when we hover a mouse over any forum-thread, & it shows the first post of that thread.

Although this feature is there in an infusion named latest active forum threads.(which is limited to & shows only the latest threads)

But i want this in the default forum that comes with php fusion, so that all the threads will show a box when we hover a mouse over it.

This is very important for me , so people dont have to open each and every forum-thread to look for the content within it .
They can simply hover their mouse over the forum thread and get a glimpse of the first post .(for me first post is important and not latest post)

Please help!