Example of a custom event in ExtJS

gistfile1.js

Ext.create('Ext.grid.Panel', {
  columns: [
    {
      xtype: 'actioncolumn',
      isDisabled: function(value) {
        return true;   
      },
      handler: function() {
        this.fireEvent('customevent', arg1, arg2, ...);
      }
    }
  ]
});

Ext.create('Ext.app.Controller', {
  init: function() {
    this.control({
      'actioncolumn' : {
        customevent: function(arg1, arg2, ...) {
          //Event Handler Function
        }
      }
    });
  }
});