Ext.Component组件可以使用userSelectable配置项，设置为‘text'，即可实现此组件中文本的点选
注意：如果设置为true，等效于设置样式 user-select: auto; ，将根据浏览器默认属性进行选择
{
 xtype: 'grid',
 userSelectable: 'text'
}

userSelectable: {
 element: true,  // allow the element to be user selectable
 bodyElement: true // allow the component's body element to be user selectable
}

{
 xtype: 'grid',
 columns: [{
 cell: { userCls: Ext.baseCSSPrefix + 'user-selectable-text' }
 }]
}

Ext.define('Ext.Component', {
 // userSelectable 各属性值对应的样式类
 userSelectableClsMap: {
  true: Ext.baseCSSPrefix + 'user-selectable-auto',
  false: Ext.baseCSSPrefix + 'user-selectable-none',
  all: Ext.baseCSSPrefix + 'user-selectable-all',
  auto: Ext.baseCSSPrefix + 'user-selectable-auto',
  text: Ext.baseCSSPrefix + 'user-selectable-text',
  none: Ext.baseCSSPrefix + 'user-selectable-none'
 },
 updateUserSelectable: function(newSelectable, oldSelectable) {
  var me = this,
   map = me.userSelectableClsMap,
   el = me.el,
   name, childEl;
 
  if (typeof oldSelectable === 'boolean' || typeof oldSelectable === 'string') {
   el.removeCls(map[oldSelectable]);
  }
  else {
   for (name in oldSelectable) {
    childEl = me[name];
 
    //<debug>
    if (!childEl || !childEl.isElement) {
     Ext.raise('Element not found: "' + name + '"');
    }
    //</debug>
 
    childEl.removeCls(map[oldSelectable[name]]);
   }
  }
 
  if (typeof newSelectable === 'boolean' || typeof newSelectable === 'string') {
   // 如果传入为布尔或字符串，直接添加对应的样式类
   el.addCls(map[newSelectable]);
  }
  else {
   // 如果传入的是对象，则根据对象属性分别给子元素添加样式类
   for (name in newSelectable) {
    childEl = me[name];
 
    //<debug>
    if (!childEl || !childEl.isElement) {
     Ext.raise('Element not found: "' + name + '"');
    }
    //</debug>
 
    childEl.addCls(map[newSelectable[name]]);
   }
  }
 },
});