Original GUISwitch.au3 example seams to not works. Here is my modified version of GUISwitch.au3 example : #include <GUIConstantsEx.au3> Example() Func Example() Local $hGUIParent1 = GUICreate("Parent1") GUICtrlCreateTab(10, 10) GUICtrlCreateTabItem("tab1") Local $idTabItem = GUICtrlCreateTabItem("tab2") GUICtrlCreateButton("OK", 50, 50, 50) GUICtrlCreateTabItem("") Local $hGUIParent2 = GUICreate("Parent2",