odoo/addons/web_view_editor/static/src/css/view_editor.css

.openerp .oe_view_editor {
  width: 100%;
  margin-left: -12px;
}
.openerp .oe_view_editor td {
  border: 1px solid #d8d8d8;
  cursor: pointer;
}
.openerp .oe_view_editor td *{
  border: 0px !important;
  color : #404040;
}
.openerp .oe_view_editor tr:hover {
  background-color: #ecebf2;
}