EnableExplicit

Define EventID

If OpenWindow(0,0,0,500,250,"Window",#PB_Window_SystemMenu|#PB_Window_ScreenCentered)
  If CreateMenu(1,WindowID(0))
    MenuTitle("Datei")
      MenuItem(1,"Item",0)
  EndIf
  
  ButtonGadget(1,10,10,100,20,"Menü entfernen",0)
  
Repeat
EventID=WaitWindowEvent()
If EventID=#PB_Event_Gadget
  Select EventGadget()
    Case 1
      SetMenu_(WindowID(0),0)
  EndSelect
EndIf
Until EventID = #PB_Event_CloseWindow
EndIf