1. I used the code from this Dynamicdrive pop it menu for this test.  See below.

2. Copy and paste code from step 1 of the dynamicdrive page into the head of the page via the Insert html code button.

3. Put a button on your site and right click it select hyperlink. In the hyperlink option box select Internet page, delete the http:// and OK out. Do not put an address in.

4. Right click button select attach html. Find the line at the point where it says
('over','tg_2')" onload="OnLoadPngFix()" __AddCode="here"></span>

At the point I’ve bolded add the codefrom the first line of the step 2
a href="#" onMouseover="showmenu(event,linkset[0])" onMouseout="delayhidemenu()"></a><br

Taking out the words “Webmaster Links” as they’ ae not needed.
If you have any trouble right click the buttons above to check out the code

Don’s WP 10 file is here    See it in action here.

—--------------

Note:  Don D has created a WP X2 file with a text box popup.
Download the X2 text popup file here.  
See the text popup in action here.

—-------------------------

This code relate to the roll over menu

HEAD CODE:
<style type="text/css">

#popitmenu{
position: absolute;
background-color: white;
border:1px solid black;
font: normal 12px Verdana;
line-height: 18px;
z-index: 100;
visibility: hidden;
}

#popitmenu a{
text-decoration: none;
padding-left: 6px;
color: black;
display: block;
}

#popitmenu a:hover{ /*hover background color*/
background-color: #CCFF9D;
}

</style>

<script type="text/javascript">

/***********************************************
* Pop-it menu- © Dynamic Drive (www.dynamicdrive.com)
* This notice MUST stay intact for legal use
* Visit http://www.dynamicdrive.com/ for full source code
***********************************************/

var defaultMenuWidth="150px" //set default menu width.

var linkset=new Array()
//SPECIFY MENU SETS AND THEIR LINKS. FOLLOW SYNTAX LAID OUT

linkset[0]='<a href="http://dynamicdrive.com">Dynamic Drive</a>'
linkset[0]+='<hr>' //Optional Separator
linkset[0]+='<a href="http://www.javascriptkit.com">JavaScript Kit</a>'
linkset[0]+='<a href="http://www.codingforums.com">Coding Forums</a>'
linkset[0]+='<a href="http://www.cssdrive.com">CSS Drive</a>'
linkset[0]+='<a href="http://freewarejava.com">Freewarejava</a>'

linkset[1]='<a href="http://msnbc.com">MSNBC</a>'
linkset[1]+='<a href="http://cnn.com">CNN</a>'
linkset[1]+='<a href="http://news.bbc.co.uk">BBC News</a>'
linkset[1]+='<a href="http://www.washingtonpost.com">Washington Post</a>'

////No need to edit beyond here

var ie5=document.all && !window.opera
var ns6=document.getElementById

if (ie5||ns6)
document.write('<div id="popitmenu" onMouseover="clearhidemenu();" onMouseout="dynamichide(event)"></div>')

function iecompattest(){
return (document.compatMode && document.compatMode.indexOf("CSS")!=-1)? document.documentElement : document.body
}

function showmenu(e, which, optWidth){
if (!document.all&&!document.getElementById)
return
clearhidemenu()
menuobj=ie5? document.all.popitmenu : document.getElementById("popitmenu")
menuobj.innerHTML=which
menuobj.style.width=(typeof optWidth!="undefined")? optWidth : defaultMenuWidth
menuobj.contentwidth=menuobj.offsetWidth
menuobj.contentheight=menuobj.offsetHeight
eventX=ie5? event.clientX : e.clientX
eventY=ie5? event.clientY : e.clientY
//Find out how close the mouse is to the corner of the window
var rightedge=ie5? iecompattest().clientWidth-eventX : window.innerWidth-eventX
var bottomedge=ie5? iecompattest().clientHeight-eventY : window.innerHeight-eventY
//if the horizontal distance isn't enough to accomodate the width of the context menu
if (rightedge<menuobj.contentwidth)
//move the horizontal position of the menu to the left by it's width
menuobj.style.left=ie5? iecompattest().scrollLeft+eventX-menuobj.contentwidth+"px" : window.pageXOffset+eventX-menuobj.contentwidth+"px"
else
//position the horizontal position of the menu where the mouse was clicked
menuobj.style.left=ie5? iecompattest().scrollLeft+eventX+"px" : window.pageXOffset+eventX+"px"
//same concept with the vertical position
if (bottomedge<menuobj.contentheight)
menuobj.style.top=ie5? iecompattest().scrollTop+eventY-menuobj.contentheight+"px" : window.pageYOffset+eventY-menuobj.contentheight+"px"
else
menuobj.style.top=ie5? iecompattest().scrollTop+event.clientY+"px" : window.pageYOffset+eventY+"px"
menuobj.style.visibility="visible"
return false
}

function contains_ns6(a, b) {
//Determines if 1 element in contained in another- by Brainjar.com
while (b.parentNode)
if ((b = b.parentNode) == a)
return true;
return false;
}

function hidemenu(){
if (window.menuobj)
menuobj.style.visibility="hidden"
}

function dynamichide(e){
if (ie5&&!menuobj.contains(e.toElement))
hidemenu()
else if (ns6&&e.currentTarget!= e.relatedTarget&& !contains_ns6(e.currentTarget, e.relatedTarget))
hidemenu()
}

function delayhidemenu(){
delayhide=setTimeout("hidemenu()",500)
}

function clearhidemenu(){
if (window.delayhide)
clearTimeout(delayhide)
}

if (ie5||ns6)
document.onclick=hidemenu

</script>