#include <WinAPI.au3>

Global $mainwindow
Global $childwin1
Global $childwin2
Global $Button_Main1
Global $Button_Child1
Global $Button_Child2

_main()

Func _main()
  $mainwindow = GUICreate("Test", 340, 500)
  $Button_Main1 = GUICtrlCreateButton("Öffne Dialog1", 120, 120, 100, 50)
  $Button_Main2 = GUICtrlCreateButton("Öffne Dialog2", 120, 180, 100, 50)

  GUISetState()
  While 1
    Switch GUIGetMsg()
        Case -3
            exit
        Case $Button_Main1
			_Childwin1()
        Case $Button_Main2
			_Childwin2()

	EndSwitch
  WEnd
EndFunc

Func _Childwin1()
  _WinAPI_SetParent($childwin1, $mainwindow)
  $Button_Child1 = GUICtrlCreateButton("Mach Was", 20, 120, 100, 50)
  GUISetState()
  While 1
    Switch GUIGetMsg()
        Case -3
            GUIDelete()
        Case $Button_Child1
            _MachWas("Hallo")
		EndSwitch
  WEnd
EndFunc

Func _Childwin2()
  _WinAPI_SetParent($childwin2, $mainwindow)
  $Button_Child2 = GUICtrlCreateButton("Mach Was anderes", 20, 180, 100, 50)
  GUISetState()
  
  While 1
    Switch GUIGetMsg()
        Case -3
            GUIDelete()
        Case $Button_Child2
            _MachWas("Tschüss")
		EndSwitch
  WEnd
EndFunc




Func _MachWas($Ausgabetext)
  MsgBox(0,"Info",$Ausgabetext)
EndFunc