Sticky hover problem in Firefox

I am creating a site and if you would click on of the images in the css gallery, a new page opens up and works properly,

but you come back to the tab the Grey box does not automatically dissappear as it does with other browser, any way I can get it working without having the user to click outside the box.

And way I could fix this?

The css code is:

#gallery {width:520px; height:115px; position:absolute; z-index:7000; left: 635px; top: 80px; }
#gallery b.default {position:absolute; left:10px; top:10px; width:548px; height:380px; text-align:left;}
#gallery b.default img {display:block; margin:0 auto 10px auto; border:1px solid #eee; border-color:#555 #ddd #eee #333;}
#gallery b.default span {display:block; color:#fff; font-family:verdana, arial, sans-serif; font-weight:normal; font-size:11px; width:350px; margin:0 auto; text-align: left;}

#gallery ul {list-style:none; padding:0; margin:0; width:180px; position:relative; float:right;}
#gallery ul li {display:inline; width:52px; height:52px; float:left; margin:0 0 5px 5px;}
#gallery ul li a {display:block; width:50px; height:50px; text-decoration:none; border:1px solid #000; border-color:#eee #555 #333 #ddd;}
#gallery ul li a span {display:none;}
#gallery ul li a img {display:block; width:50px; height:50px; border:0;}
#gallery ul li a:hover {white-space:normal; border-color:#555 #ddd #eee #333; background-image: url(<?php bloginfo('template_url'); ?>/images/bg_img.jpg);}
#gallery ul li a:hover b {position:absolute; left:-300px; top:0; width:100px; height:100px; text-align:center; z-index:20;}
#gallery ul li a:hover span {display:block; color:#fff; font-family:verdana, arial, sans-serif; font-weight:normal; font-size:11px; width:350px; text-align:left;}
#gallery ul li a:hover img {margin:0 auto 10px auto; width:auto; height:auto;}

#gallery ul li a:active, #gallery ul li a:focus {white-space:normal; border-color:#555 #ddd #eee #333; background:#777;}
#gallery ul li a:active b, #gallery ul li a:focus b {position:absolute; left:-300px; top:0; width:100px; height:100px; text-align:center; z-index:10;}
#gallery ul li a:active span, #gallery ul li a:focus span {display:block; color:#fff; font-family:verdana, arial, sans-serif; font-weight:normal; font-size:11px; width:350px; margin:0 auto; padding-right: 30px;}
#gallery ul li a:active img, #gallery ul li a:focus img{margin:0 auto 10px auto; width:auto; height:auto; border:1px solid #eee; border-color:#555 #ddd #eee #333;}

Code (markup):

HTML CODE:

 <div id="gallery">
<ul>
	<li><a href="http://www.etsy.com/view_listing.php?listing_id=19132282" target="_blank"><b><img src="<?php bloginfo('template_url'); ?>/images/gallery/1.jpg" title="" alt="" /><span>This is T1</span></b></a></li>
	<li><a href="http://www.etsy.com/view_listing.php?listing_id=19132432" target="_blank"><b><img src="<?php bloginfo('template_url'); ?>/images/gallery/2.jpg" title="" alt="" /><span>More T2</span></b></a></li>
	<li><a href="http://www.etsy.com/view_listing.php?listing_id=18998269" target="_blank"><b><img src="<?php bloginfo('template_url'); ?>/images/gallery/3.jpg" title="" alt="" /><span>Descriptive text can be placed below the image.<br> Testing out with more text. Over here with more.</span></b></a></li>
	<li><a href="http://www.etsy.com/view_listing.php?listing_id=19133014" target="_blank"><b><img src="<?php bloginfo('template_url'); ?>/images/gallery/4.jpg" title="" alt="" /><span>You can style the descriptive text as you like</span></b></a></li>
	<li><a href="http://www.etsy.com/view_listing.php?listing_id=19133346" target="_blank"><b><img src="<?php bloginfo('template_url'); ?>/images/gallery/5.jpg" title="" alt="" /><span>Place the descriptive text in a span tag</span></b></a></li>
	<li><a href="http://www.etsy.com/view_listing.php?listing_id=19133606" target="_blank"><b><img src="<?php bloginfo('template_url'); ?>/images/gallery/6.jpg" title="" alt="" /><span>Photograph descriptive text here</span></b></a></li>
</ul>
</div>

Code (markup):

 

167 HTML errors
10 CSS errors.

 

still doesn't help me out with the gallery.