Q:

Displaying third tier submenus properly with css only menu

I am developing a new site, and am having problems with the css menu. It is easier to explain by example:  Here is the link of the site: http://www.webau.net/CSFF/index.asp
Under the "Home" parent menu item, I have the following configuration:
Top level menu (parent)
    Submenu 1 (child 1)
        Submenu 2 (grandchild 1)
    Submenu 3 (child 2)
    Submenu 4 (child 3)

Instead it appears on the page like this where the grandchild 1 looks like it takes the place of the child 2 menu:
Top level menu (parent)
    Submenu 1 (child 1)
    Submenu 2 (grandchild 1)
    Submenu 4 (child 3)

I can see a slight offset on the listing of Submenu 2.. which makes me think it is an attempt to display the grandchild inappropriately.
So I am assuming I have two problems.. 
First is that the third tier menu (grandchild submenu 2) is displaying at the same time the second tier menus (child submenus 1, 3, 4) display when you hover over the parent menu item.  
And second is that for some reason the grandchild submenu 2 item is displacing (laying ontop of) the child submenu 3.
I think problem two will be fixed when I correct the display of the grandchild submenu.
Can someone help me figure out how to add new css code to deal with the third tier or multi- tier menus .. so they are hidden until their own parent is hovered, and to then display to the right of it's parent's submenu column?
Thanks again for your help.
SunnyOz
For your convenience:
HTML Code:
<div id="navcontainer">
    <div id="navsection">  
        <ul>
            <li id="navactive"><a class="current" href="#">Home</a>
                <ul>
                    <li><a href="#">submenu 1</a>
                        <ul>
                            <li><a href="#">submenu 2</a></li>
                        </ul>
                    </li>
                    <li><a href="#">submenu 3</a></li>
                    <li><a href="#">submenu 4</a></li>
                </ul>
            </li>
            <li><... rest of menu items not needed for example>
            </li>
        </ul>
    </div>
</div>

CSS Code:
#navcontainer 
{
    width: 711px;
    height: 25px;
    text-align: center;
    margin: 0px auto; /*Center container on page*/
    clear: both;
    background-color: #129F9F;
    border: 3px solid #FFFFFF;
    -moz-border-radius: 5px;
    -webkit-border-radius: 5px;
    -o-border-radius: 5px;
    -ms-border-radius: 5px;
    border-radius: 5px; 

    /* IE10 Consumer Preview */ 
    background-image: -ms-linear-gradient(top, #16ACAC 0%, #0D6F6F 100%);

    /* Mozilla Firefox */ 
    background-image: -moz-linear-gradient(top, #16ACAC 0%, #0D6F6F 100%);

    /* Opera */ 
    background-image: -o-linear-gradient(top, #16ACAC 0%, #0D6F6F 100%);

    /* Webkit (Safari/Chrome 10) */ 
    background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0, #16ACAC), color-stop(1, #0D6F6F));

    /* Webkit (Chrome 11+) */ 
    background-image: -webkit-linear-gradient(top, #16ACAC 0%, #0D6F6F 100%);

    /* W3C Markup, IE10 Release Preview */ 
    background-image: linear-gradient(to bottom, #16ACAC 0%, #0D6F6F 100%); 
}
#navsection
{
    height: 24px;
    line-height: 24px;
    font-size: 12px;
    position: relative;
}
#navsection ul
{
    padding: 0px 0px 0px 35px;  /* padding on left to get nav menu to center.. since it has a float left to make it display properly*/
    list-style: none;
}
#navsection ul li
{
    padding: 0;
    margin: 0;
    border-right: 2px solid #129F9F;
    float: left;
}
#navsection ul li.navcontact  /* to stop right border at end of nav line */
{
    padding: 0;
    margin: 0;
    border-right: none;
    float: left;
}
#navsection ul li a
{
    color: #FFF;
    display: block;
    text-decoration: none;
    padding: 0 15px;
}
#navsection > ul > li > a:hover, #navsection  > ul > li:hover > a  
{  
    text-decoration: none;
    color: #EAA339;
    /* IE10 Consumer Preview */ 
    background-image: -ms-linear-gradient(top, #0D6F6F 0%, #16ACAC 100%);

    /* Mozilla Firefox */ 
    background-image: -moz-linear-gradient(top, #0D6F6F 0%, #16ACAC 100%);

    /* Opera */ 
    background-image: -o-linear-gradient(top, #0D6F6F 0%, #16ACAC 100%);

    /* Webkit (Safari/Chrome 10) */ 
    background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0, #0D6F6F), color-stop(1, #16ACAC));

    /* Webkit (Chrome 11+) */ 
    background-image: -webkit-linear-gradient(top, #0D6F6F 0%, #16ACAC 100%);

    /* W3C Markup, IE10 Release Preview */ 
    background-image: linear-gradient(to bottom, #0D6F6F 0%, #16ACAC 100%); 
}

#navsection > ul > li > a.current:hover, #navactive a.current:link, #navactive a:visited, #navactive > ul  li  a:hover, #navsection a:hover
{
    text-decoration: none;
    color: #EAA339;
    /* IE10 Consumer Preview */ 
    background-image: -ms-linear-gradient(top, #0D6F6F 0%, #16ACAC 100%);

    /* Mozilla Firefox */ 
    background-image: -moz-linear-gradient(top, #0D6F6F 0%, #16ACAC 100%);

    /* Opera */ 
    background-image: -o-linear-gradient(top, #0D6F6F 0%, #16ACAC 100%);

    /* Webkit (Safari/Chrome 10) */ 
    background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0, #0D6F6F), color-stop(1, #16ACAC));

    /* Webkit (Chrome 11+) */ 
    background-image: -webkit-linear-gradient(top, #0D6F6F 0%, #16ACAC 100%);

    /* W3C Markup, IE10 Release Preview */ 
    background-image: linear-gradient(to bottom, #0D6F6F 0%, #16ACAC 100%); 
}

#navsection ul li ul
{
    display: none;
    width: auto;
    position: absolute;
    padding: 0px;
    margin: 0px;
}
#navsection ul li:hover ul
{
    display: block;
    position: absolute;
    margin: 0;
    padding: 0;
}
#navsection ul li:hover li
{
    float: none;
    list-style: none;
    margin: 0px;
}
#navsection ul li:hover li
{
    font-size: 12px;
    height: 24px;
    background: #54C4C4;
    border: 1px solid #FFFFFF;
    -moz-border-radius: 5px;
    -webkit-border-radius: 5px;
    -o-border-radius: 5px;
    -ms-border-radius: 5px;
    border-radius: 5px; 
}
#navsection ul li:hover li a
{
    font-size: 11px;
    color: #fff;
    padding: 0px;
    display: block;
    width: 150px;
}
#navsection ul li li a:hover
{
    font-size: 11px;
    height: 24px;
    color:#EAA339;
    -moz-border-radius: 5px;
    -webkit-border-radius: 5px;
    -o-border-radius: 5px;
    -ms-border-radius: 5px;
    border-radius: 5px; 
}

A:

There are 3 issues here.

You are displaying all <ul/> elements that exist below a hovered <li/>.
Change #navsection ul li:hover ul to #navsection ul li:hover > ul to select the immediate child only
You are setting the position of each drop level to be the same.
Try adding something like #navsection ul ul ul { top: 1em; left: 140px; }, this will stop the grandchild obscuring the child.
You're title attributes are negatively affecting your navigation.
I'd remove them entirely as they do not add any real beneficial information to the link and obscure the menu items making the navigation difficult to use.

I hope that helps :)

