ExtJS布局在firefox浏览器中汉字显示为较小，原因是ExtJS的ext-all.css中font-size的单位为em，firefox对汉字大小的解析与其他浏览器不一致。

解决方法如下（转载）：

在导入ext-all.css后，再添加ext-patch.css。

.x-window-footer {
       position: relative;    top: 0;    right: 0;}.x-tab-strip SPAN.x-tab-strip-text {
       font-size: 12px;}.x-panel-header {
       font-size: 12px;}.x-tree-node {
       font-size: 12px;}.x-grid3-hd-row TD {
       font-size: 12px;}.x-grid3-row TD {
       font-size: 12px;    LINE-HEIGHT: 16px;}.x-orange-class {
       background: #ffb11c;}.x-yellow-class {
       background: #ff0;}.x-tip .x-tip-bd {
       font-size: 12px;}.x-tip h3{
       font-size: 12px;}.x-tip .x-tip-bd-inner{
       font-size:12px;}.x-panel-tl .x-panel-header {
       FONT: normal 12px tahoma,arial,verdana,sans-serif;}.x-form-field {
       FONT: 12px tahoma,arial,helvetica,sans-serif    }.x-small-editor .x-form-field {
       FONT: 12px tahoma,arial,helvetica,sans-serif    }.x-combo-list-item {
       FONT: 12px tahoma,arial,helvetica,sans-serif;    }    .x-menu-list-item {
       FONT: 12px tahoma,arial,sans-serif;}.x-window-tl .x-window-header {
       FONT: bold 12px tahoma,arial,verdana,sans-serif;    }.x-layout-split-west .x-layout-mini {
           BACKGROUND-IMAGE: url(../images/mini-left.jpg);    }.ext-ie .x-form-text {
       margin-top:1px;} /* the textField missing bottom line */.x-form-item {
           FONT: 12px tahoma,arial,helvetica,sans-serif}.x-grid-group-hd DIV {
           FONT: bold 12px tahoma,arial,helvetica,sans-serif;}.x-btn-text-icon .x-btn-center .x-btn-text {
   background-position:0pt 1px;background-repeat:no-repeat;padding:0px 0pt 0px 18px;}.ext-gecko .x-btn button {
   padding-left:0pt;padding-right:0pt;}.x-btn button{
       font-size:12px;}.x-toolbar td, .x-toolbar span, .x-toolbar input, .x-toolbar div, .x-toolbar select, .x-toolbar label {
       font-size:12px;}.x-fieldset legend {
       font-size:12px;}.x-tip .x-tip-body {
       font-size:12px;}.controlBtn img {
                   cursor: pointer;            }.x-grid3-summary-row{
   border-left:1px solid #fff;border-right:1px solid #fff;color:#333;background: #f1f2f4;}.x-grid3-summary-row .x-grid3-cell-inner{
   font-weight:bold;padding-bottom:4px;font-size:12px;}.x-grid3-cell-first .x-grid3-cell-inner{
   padding-left:16px;}.x-grid-hide-summary .x-grid3-summary-row{
   display:none;}.x-grid3-summary-msg{
   padding:4px 16px;font-weight:bold;}.negative{
   color:#dd0000;}.positive{
   color:green;}.x-grid3-body .x-grid3-td-cost{
   background-color:#f1f2f4;}.x-grid3-summary-row .x-grid3-td-cost{
   background-color:#e1e2e4;}.x-grid3-dirty-cell{
   background-image:none;}