Fehler Artikelübersicht

Hallo zusammen,

neuerdings kann ich die Artikelübersicht im Backend nicht mehr aufrufen. Es tut sich nichts beim Klick dadrauf. Stattdessen sehe ich in der Browser-Konsole folgenden Fehler:

Uncaught TypeError: Cannot read property ‚on‘ of undefinedExt.define.initComponent @ /shopware/backend/ArticleList/load/?f=m/Filter|m/EditableColumn|m/Operation|m/Operator|v/main/Windo…:608Ext.define.constructor

@ ext-all.js?201505131100:21b.implement.callParent @ ext-all.js?201505131100:21Ext.define.constructor @ ext-all.js?201505131100:21i @ ext-all.js?201505131100:21Ext.apply.widget @ ext-all.js?201505131100:21Ext.define.create @ ext-all.js?201505131100:21Ext.define.lookupComponent @ ext-all.js?201505131100:21Ext.define.prepareItems @ ext-all.js?201505131100:21Ext.define.add @ ext-all.js?201505131100:21Ext.define.initItems @ ext-all.js?201505131100:21b.implement.callParent @ ext-all.js?201505131100:21Ext.define.initItems @ ext-all.js?201505131100:21Ext.define.initComponent @ ext-all.js?201505131100:21b.implement.callParent @ ext-all.js?201505131100:21Ext.define.initComponent @ ext-all.js?201505131100:21b.implement.callParent @ ext-all.js?201505131100:21Ext.define.initComponent @ ext-all.js?201505131100:21b.implement.callParent @ ext-all.js?201505131100:21Ext.override.initComponent @ base?file=bootstrap&loggedIn=1458508740:1273b.implement.callParent @ ext-all.js?201505131100:21Ext.define.initComponent @ ext-all.js?201505131100:21b.implement.callParent @ ext-all.js?201505131100:21Ext.define.initComponent @ base?file=bootstrap&loggedIn=1458508740:1646b.implement.callParent @ ext-all.js?201505131100:21Ext.define.initComponent @ /shopware/backend/ArticleList/load/?f=m/Filter|m/EditableColumn|m/Operation|m/Operator|v/main/Windo…:89Ext.define.constructor @ ext-all.js?201505131100:21b.implement.callParent @ ext-all.js?201505131100:21Ext.define.constructor @ ext-all.js?201505131100:21i @ ext-all.js?201505131100:21(anonymous function) @ VM191:1Ext.ClassManager.instantiate @ ext-all.js?201505131100:21(anonymous function) @ ext-all.js?201505131100:21Ext.apply.create @ ext-all.js?201505131100:21Ext.define.bindStores @ /shopware/backend/ArticleList/load/?f=m/Filter|m/EditableColumn|m/Operation|m/Operator|v/main/Windo…:2054Ext.define.createDetailModel @ /shopware/backend/ArticleList/load/?f=m/Filter|m/EditableColumn|m/Operation|m/Operator|v/main/Windo…:2050Ext.Ajax.request.success @ /shopware/backend/ArticleList/load/?f=m/Filter|m/EditableColumn|m/Operation|m/Operator|v/main/Windo…:1985Ext.apply.callback @ ext-all.js?201505131100:21Ext.define.onComplete @ ext-all.js?201505131100:21Ext.define.onStateChange @ ext-all.js?201505131100:21(anonymous function) @ ext-all.js?201505131100:21

Hat vielleicht jemand eine Idee woran das liegen könnte?

Vielen Dank im Voraus!