When i display my data from the store in a list , all my items are multiplied, each time i load my app (F5)

var imagStore=Ext.create('Ext.data.Store', {
                        model: 'CWFSE.model.Document',// use a model
                        data: record.get('docs'), // set the store data as the doc array
      //ref to my list view
this code works perfectly well in 2.03 version, but in 2.1, the items are multiplied

Someone can help me with this ? Is this a bug or something i'm doing wrong ?