This arose from a topic in the help forum and I'm just cross-posting here at Sandin's suggestion. The problem was how to monitor messages going to another window not controlled by AutoIt. After much searching I found a suitable workaround. First of all you need to download this package: Unzip dssubcls.dll in to the same folder as your script. You can then use it to "subclass" any other window. My example in Notepad: #include <Win