[Plugin: custom tables] 2 questions to know if it's possible

1. How to highlight a line when the mouse goes over ? with the overlay function ?

You need to use the CSS Class wct-td-hover

2. How to display the 5th field of the 6th entry ? with [wcteid] ?

wcteid will show ONE entry of the database (the Entry setup).
If you enter in the entry setup only the field5, it will only be displayed. Find the ID of line 5 and add it. Use the Smarttag Generator.

What do you want to to do? Very strange ^^

I don’t think ths css is specific to the plugin, but I could be wrong about that. Most plugins use your theme’s style rules, the same it would apply to all instance of hover..
maybe looks like this:

#wct-td-hover {
color:#999999
}

I don’t know if the link you posted is your site or an example of what you want, in any case I can’t find a table. otherwise I could probably find the css.

this appears to be the global hover code for a links

a, a:link, a:hover {
    color: #CC0000;
    text-decoration: none;
}

but as I frequently find when I look at code in Firebug, it’s crossed out and not applied to the instance in the table. I don’t understand why that is the case, one of the thngs about Firebug I’ve yet to understand.

Change the color number and put it at the bottom of style.css, see if it works. it will most likely effect hover color on your whole site.

I didn’t know what you meant before, but yes, that’s the way to do it.