.x-grid-checkheader {height: 14px;background-image: url('images/unchecked.gif');background-position: 50% -2px;background-repeat: no-repeat;background-color: transparent;}.x-grid-checkheader-checked {background-image: url('images/checked.gif');}.x-grid-checkheader-editor .x-form-cb-wrap {text-align: center;}