One of my first guesses was that sometimes divs, cells, etc won't show right without something in them. I added between the first and last cells of active and nonactive tabs and it showed up in IE.
<td class="maintab_first"> </td>You can also reduce the CSS for the tabs a lot. For the section I made changes the CSS was reduced from 55 lines and 936 char to 27 lines and 433 char. I found having the same width of 10px on all tabs didn't look any different in the browsers.
Here is my sandbox tested in IE 6 and Firefox 2.0.0.12. The
CSS file contains two versions (noted by comments). One is little more repetitive but maybe easier to read, the other is consolidated version.
Consolidated version:
.mirrortab_first, .mirrortab_back, .mirrortab_last
{
background: #808080;
width: 10px;
border-top: 1px solid #FFFF00;
}
.mirrortab_first{
border-left: 1px solid #FFFF00;
}
.mirrortab_last
{
border-right: 1px solid #FFFF00;
}
.mirrortab_active_first, .mirrortab_active_back, .mirrortab_active_last
{
background: #c0c0c0;
width: 10px;
border-top: 2px solid #FFFF00;
}
.mirrortab_active_first
{
border-left: 2px solid #FFFF00;
}
.mirrortab_active_last
{
border-right: 2px solid #FFFF00;
}