There is an exception when trying to add the event listener. The code is reused from this article - https://docs.telerik.com/teststudio/testing-framework/write-tests-in-code/advanced-topics-wtc/javascript-wtc/javascript-events#javascript-event-handlers Expected: successful run Actual: an exception is thrown. InnerException: ArtOfTest.WebAii.Exceptions.ExecuteCommandException: ExecuteCommand failed! InError set by the client. Client Error: this.eventHandlers is undefined BrowserCommand (Type:'Action',Info:'NotSet',Action:'AttachEventHandler',Target:'ElementId (tagName: 'input',occurrenceIndex: '5')',Data:'click--@@--21e26bef-07eb-4e5b-b383-3e91f4b50f9b',ClientId:'fa1e60f0-697c-4d4b-bda7-a0c37a473a96',HasFrames:'False',FramesInfo:'',TargetFrameIndex:'-1',InError:'True',Response:'this.eventHandlers is undefined')