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<System.Runtime.CompilerServices.Extension()>
Friend Function GetAllControlsOfType(Of T As Control)(ByVal controls As Control.ControlCollection) As T()
  Dim controlsArray(controls.Count - 1) As Control
  controls.CopyTo(controlsArray, 0)
  Dim oldControlSieveList As New List(Of Control)(controlsArray)
  Dim newControlSieveList As List(Of Control)
  Dim targetControlList As New List(Of T)
  While oldControlSieveList.Count > 0
    newControlSieveList = New List(Of Control)
    For Each parentControl As Control In oldControlSieveList
      If parentControl.HasChildren Then
        For Each childControl As Control In parentControl.Controls
          newControlSieveList.Add(childControl)
        Next
      End If
      If TypeOf parentControl Is T Then targetControlList.Add(parentControl)
    Next
    oldControlSieveList = newControlSieveList
  End While
  Return targetControlList.ToArray
End Function