This folder contains two scripts: "Custom draw, GUI.au3" and "Custom draw, Childs.au3". The code in these scripts is exactly the same code as shown in post 37 (https://www.autoitscript.com/forum/topic/180885-how-to-use-all-messages-in-guigetmsg/?do=findComment&comment=1299218) and 38 of the thread named "How to use all messages in GuiGetMsg()" in "AutoIt General Help and Support" forum. I'll refer to these posts for information about the two scripts.
