I've been working on this fun project for a few hours as it turns out its not so fun anymore. LOL but I'm determined. Does anyone got ideas why this isn't working? I know that there is a rule missing, I didn't get that far. Thanks for your help #include <GUIConstantsEx.au3> #include <WindowsConstants.au3> #include <EditConstants.au3> #include <Array.au3> Opt("GUIOnEventMode", 1) ; My idea is that of a graph with x,y cordinates. One array points to the edit control