title: Dynamic Combo Box Drop down list based on the adjacent column array List
body: <p>I have a JSON store defined as </p>
  
  <pre><code>var reader = new Ext.data.JsonReader({
      id: 'id',
      totalProperty: 'totalCount',
      root: 'rows',
      fields: [{
          name: 'id'
      }, {
          name: 'seriesId',
          type: 'string'
      }, {
          name: 'seriesTitle',
          type: 'string'
      }, {
          name: 'productionId',
          type: 'string'
      }, {
          name: 'triggered',
          type: 'string'
      }, {
          name: 'partnerName',
          type: 'string'
      }, {
          name: 'partnerId',
          type: 'string'
      }, {
          name: 'startDate',
          type: 'date'
      }, {
          name: 'startDate0',
          mapping: 'startDate',
          type: 'date'
      }, {
          name: 'endDate',
          type: 'date'
      }, {
          name: 'drmType',
          type: 'string'
      }, {
          name: 'defaultDrmType',
          type: 'string'
      }
  
      ]
  });
  
  var conn = new Ext.data.Connection({
      url: '/SyndicationPlatform/masterDrmStore/listJson',
      timeout: 300000
  });
  
  var proxy = new Ext.data.HttpProxy(conn);
  
  var store = new Ext.data.GroupingStore({
      reader: reader,
      url: '/SyndicationPlatform/masterDrmStore/listJson',
      proxy: proxy,
      autoLoad: 'true',
      //,groupField: ['seriesPartner']
      remoteSort: true
  });
  
  I have a Column Model defined as below
  for the above json store.
  
  var cm = new Ext.grid.ColumnModel([{
      header: "&lt;div class=\"x-grid3-hd-checker\" style=\"width: 26px;\"&gt;",
      id: "priority",
      width: 35,
      sortable: false,
      resizable: false,
      menuDisabled: true,
      fixed: true,
      renderer: function (data, cell, record, rowIndex, columnIndex, store) {
          if (data) {
              var today = new Date();
              var startDate = new Date(record.data.startDate);
              var out = '&lt;div';
              out += (startDate &lt; today) ? ' class="red-row" id="red-row"' : ((startDate &lt; new Date(today.getTime() + 3 * 24 * 60 * 60 * 1000)) ? ' class="orange-row" id="orange-row"' : ((startDate &lt; new Date(today.getTime() + 8 * 24 * 60 * 60 * 1000)) ? ' class="blue-row" id="blue-row"' : ' class="green-row" id="green-row"'));
              out += '&gt;';
              if (record.data.isLicenceUpdated == true) out += '&lt;img src="/SyndicationPlatform/images/skin/exclamation.png" class="icon-updated"/&gt;';
              else out += "";
              if (record.data.deliverable) {
                  out += '&lt;div class="x-grid3-row-checker" id="x-grid3-row-checker"&gt;&lt;/div&gt;';
              }
              out += '&lt;/div&gt;';
              return out;
          }
      },
      dataIndex: 'startDate0'
  }, {
      header: "Partner",
      id: "partner",
      editor: new Ext.form.TextField({
          readOnly: true
      }),
      width: 35,
      sortable: true,
      dataIndex: 'partnerName'
  }, {
      header: "Type",
      id: "archiveCatchup",
      editor: new Ext.form.TextField({
          readOnly: true
      }),
      width: 50,
      sortable: true,
      dataIndex: 'triggered'
  }, {
      header: "Series",
      id: "seriesPartner",
      editor: new Ext.form.TextField({
          readOnly: true
      }),
      width: 50,
      sortable: false,
      hideable: false,
      hidden: true,
      dataIndex: 'seriesPartner'
  }, {
      header: "Licence ID",
      id: "licId",
      editor: new Ext.form.TextField({
          readOnly: true
      }),
      width: 100,
      sortable: true,
      dataIndex: 'id'
  }, {
      header: "Production ID",
      id: "prodId",
      editor: new Ext.form.TextField({
          readOnly: true
      }),
      width: 87,
      sortable: true,
      dataIndex: 'productionId'
  }, {
      header: "Series ID",
      id: "seriesId",
      editor: new Ext.form.TextField({
          readOnly: true
      }),
      width: 50,
      sortable: true,
      dataIndex: 'seriesId',
      hidden: true
  }, {
      header: "DRM List",
      id: "drmList",
      editor: new Ext.form.TextField({
          readOnly: true
      }),
      width: 50,
      sortable: true,
      dataIndex: 'drmList',
      hidden: true
  }, {
      header: "Series Title",
      id: "seriesTitle",
      editor: new Ext.form.TextField({
          readOnly: true
      }),
      width: 190,
      sortable: true,
      dataIndex: 'seriesTitle',
      hidden: false
  }, {
      header: "Start Date",
      id: "startDate",
      editor: new Ext.form.DateField({
          readOnly: true,
          hideTrigger: true,
          format: 'd/m/Y'
      }),
      width: 65,
      sortable: true,
      renderer: Ext.util.Format.dateRenderer('d/m/Y'),
      dataIndex: 'startDate'
  }, {
      header: "End Date",
      id: "endDate",
      editor: new Ext.form.DateField({
          readOnly: true,
          hideTrigger: true,
          format: 'd/m/Y'
      }),
      width: 65,
      renderer: Ext.util.Format.dateRenderer('d/m/Y'),
      sortable: true,
      dataIndex: 'endDate'
  }, {
      header: "DRM Type",
      id: "drmType",
      editor: new Ext.form.ComboBox({
          mode: 'local',
          forceSelection: true,
          id: 'drm-combo'
          typeAhead: true,
          selectOnFocus: true,
          triggerAction: 'all',
          displayField: 'name',
          valueField: 'name',
          store: new Ext.data.JsonStore({
              autoLoad: true,
              url: '/SyndicationPlatform/masterDrmStore/jsonDrmTypelist',
              root: 'items',
              fields: ['name']
          })
      }),
      width: 80,
      sortable: true,
      dataIndex: 'drmType'
  },
  rowActions]);
  </code></pre>
  
  <p>I would like to have the drop down list for combo box as the value from corresponding header: "DRM List".</p>
  
  <p>How can I achieve this? Any help on this would be appreciated. Thanks</p>