Hello,
Thanks a lot, you learn me a new thing !
The solution was :
.et-db #et-boc .et-l .et_pb_row .et_pb_column.et-last-child, .et-db #et-boc .et-l .et_pb_row .et_pb_column:last-child, .et-db #et-boc .et-l .et_pb_row_inner .et_pb_column.et-last-child, .et-db #et-boc .et-l .et_pb_row_inner .et_pb_column:last-child {
z-index: initial;
}