The codes not hard to script, was hard to think of before i needed it myself, i did something similar where i wanted a list box on the left and right, but i didnt want a real lsitbox on the left, since i also wanted to be able to copy and paste from it. In mine i invert using ctrl-r the line the mouse is on in the hotlink, removing it from the previous line. So its like one constantly highlighting line. But for your need i simply enabled u to get the line number the mouse is on during a right click.

Code:
on ^1:HOTLINK:*:@windowname:{ set %windowname.lastpos $mouse.x $mouse.y $hotlinepos }
menu @windowname {
  rclick:{ if ($mouse.x $mouse.y == $gettok(%windowname.lastpos,1-2,32)) { dline @windowname $gettok(%windowname.lastpos,4,32)) } }
}


* only bad thing is this doesnt deal with you right clicking over spaces in the line, but well to bad! lol

* replace all occrances of "windowname" including in the sets with YOUR windows name.

* if you dont want the fingerpointer add a | HALT to the end of the hotlink, but this makes for not so easy to spot that u need to be over text, and the mouse never changes.

%windowname.lastpos contains 4 space seperated values that were pulled at the last hotlink event (mouse over text event) mousex mousey word# line#

(word# is which word the mouse is over, u likely dont need it, but i left it in incase you have a brain flash for something else)