@Melba23   You inspired me.  But tell me what you think of such a modification: #include <GuiConstantsEx.au3> #include <GuiTab.au3> #include <StaticConstants.au3> ; Tab colours Global $aTabColours[4] = [0xFFC0C0, 0xC0FFC0, 0xC0C0FF, 0xC0C0C0] ; Create GUI Global $hGUI = GUICreate ("Test", 400,300) GUISetBkColor (0) ; Create label to cover tab "tab" Global $ahColourTab[4] For $i = 0 to 3 $ahColourTab[$i] = GUICtrlCreateLabel("", 0, 0, 1, 1, BitOR($SS_NOTIFY, $SS_CENTER, $