By adding a wrapper div around the <ul> lists, you can have a dropdown that doesn't shift the following rows. Replace the center section of code with this
PHP Code:
$um_size = ($unique_model->RecordCount());
if($um_size) {
$col_max_item = ceil($um_size/4);
$content .= '<div class="mfrListCols"><ul class="first">' . "\n";//added div
while (!$unique_model->EOF) {
if($col_count >= $col_max_item){
$col_count = 0;
$content .= '</ul>' . "\n" . '<ul>' . "\n";
}
$content .= ' <li><a href="index.php?main_page=advanced_search_result&search_in_description=1 keyword=' .$unique_model->fields['products_model_number']. '" alt="alt name" />' .$unique_model->fields['products_model_number']. '</a></li>' . "\n";
$col_count ++;
$unique_model->MoveNext();
}//uniq
$content .= '</ul></div>' . "\n";//added /div
}//size
and modify stylesheet rules
Code:
<style>
/*stylesheet rules*/
#modelList {}
.mfrList {margin: 0.5em; padding: 0.5em; border-bottom: 1px solid #aabbcc; position: relative;}
#modelList h3 {text-align: center;}
#modelList ul {float: left; width: 24.5%; margin: 0; padding: 0; border-left: 1px solid #aabbcc;}
#modelList ul.first {border: none;}
#modelList li {list-style: none; padding: 0 0 0 1.0em;}
#modelList a {color: #0099cc;}
#modelList .mfrList .mfrListCols {display: none;}
#modelList .mfrList:hover .mfrListCols {display: block; position: absolute; width: 100%; background: #ffffcc; padding: 0.5em 0; border-bottom: 1px solid #aabbcc;}
</style>