When deleting steps one by one very fast and you have some of the steps unchecked Test Studio throws Index out of range exception as pasted below:

[03/03 15:40:56,Telerik.TestStudio.exe(13856:1),TestStudio] TestExplorerController.ExecuteCommand() : EXCEPTION! (see below)
     Outer Exception Type: System.ArgumentOutOfRangeException
     Message: Index was out of range. Must be non-negative and less than the size of the collection.
          Parameter name: index
     HRESULT: 0x80131502 (Official ID (if app.) = COR_E_ARGUMENTOUTOFRANGE, Error Bit = FAILED, Facility = FACILITY_URT, Code = 5378)
     Call Stack:
          at System.ThrowHelper.ThrowArgumentOutOfRangeException()
          at System.Collections.Generic.List`1.get_Item(Int32 index)
          at ArtOfTest.WebAii.Design.UI.TestExplorerController.RemoveStepInternal(StepData stepIdentification)
          at ArtOfTest.WebAii.Design.UI.TestExplorerController.<RemoveSteps>b__5a(StepData s)
          at System.Collections.Generic.List`1.ForEach(Action`1 action)
          at ArtOfTest.WebAii.Design.UI.TestExplorerController.<RemoveSteps>b__59(DoUndoItem doUndo)
          at ArtOfTest.WebAii.Design.UI.UndoRedoHelper.CreateDoUndoItem[T](T data, Action`1 execute, Action`1 unexecute, Boolean addToUndoStack, Boolean callExecute, Object registeredObject)
          at ArtOfTest.WebAii.Design.UI.TestExplorerController.RemoveSteps(FlatListViewModel flatListViewModel, Boolean addToUndoStack, Boolean removeCodeBehind, Boolean storeCodeBehind)
          at ArtOfTest.WebAii.Design.UI.TestExplorerController.ExecuteCommand(ICommand command, Object parameters)

Here is a short video demonstration:  http://screencast.com/t/fHghTpJFm

Test Studio version 2014.4.1411