Why is Firefox missing the border on some HTML tables

Question

I am using Firefox 3.5.7 and I have the same CSS used in multiple HTML tables, but there are some examples where parts of the borders are not shown.

What makes no sens

Answer 1

worked for me realisation of answer @Donald Payne

*( .table - bootstrap class )

table.table {
    border-collapse: separate !important;
}

table.table tr,
table.table th,
table.table td {
    border-right-width: 0 !important;
    border-bottom-width: 0 !important;
    border-left: 1px solid #DDD !important;
    border-top: 1px solid #DDD !important;
}

table.table td:last-child,
table.table th:last-child {
    border-right: 1px solid #DDD !important;
}

table.table tr:last-child td {
    border-bottom: 1px solid #DDD !important;
}

table.table {
    border: 0 !important;
}

table.table thead tr:last-child th,
table.table thead tr:last-child td {
  border-bottom: 1px solid #DDD !important;
}

table.table tbody tr:first-child th,
table.table tbody tr:first-child td {
  border-top-width: 0 !important;
}