With the new CSS tabs in version 4.0 of the cart, the setting in the product details page for tab height/width is no longer needed, the tab's height / width automatically adjust. However, module.css needs to be edited to correct the width not automatically fitting the text. To do this, open the module.css file for the Product Detail module, and replace this:

.tab_container {

with:

.tab_container {

Thanks for bringing this to our attention,

Christian

Sorry, you will also need to change the ul.tabs from this:

ul.tabs {
    margin: 0;
    padding: 0;
    float: left;
    list-style: none;     height: 32px; /*--Set height of tabs--*/
    border-bottom: 1px solid #999;
    border-left: 1px solid #999;
    width: 770px;
}

ul.tabs {
    margin: 0;
    padding: 0;
    float: left;
    list-style: none;     height: 32px; /*--Set height of tabs--*/
    border-left: 1px solid #999;
    width: 100%;
}