Procedure Progress(*x)
  While a=0
  SetGadgetState(2, Value)  
  Delay(10)
  If Value=100:Value=0:EndIf
  Value+1
  Wend
EndProcedure  

OpenWindow(0, 0, 0, 400, 100, "Create Thread", #PB_Window_SystemMenu|#PB_Window_ScreenCentered)
  ProgressBarGadget(2, 10, 10, 380, 20, 0, 100)
  CreateThread(@Progress(), 0)

Repeat  
  Event = WaitWindowEvent()  
Until Event = #PB_Event_CloseWindow