Terence, insert an html fragment in an empty space on the background layer
and write the following code:

<STYLE>
<!--
A:link {text-decoration:none}
A:active {text-decoration:none}
A:visited {text-decoration:none}
A:hover {color:rgb(###,###,###)}
-->
</STYLE>

Note:### stands for a number from 0 to 255. Check the 3 numbers
corresponding to your the colour you want on your colour chart. You can add
other properties, like text-decoration:underline and/or font-weight:bolder
after the color specification, but you must separate them with a space and a
semi-colon.