Thank you very much Danny. That may have been a good near-solution, but unfortunately keystrokes like NumLock, CapsLock and friends are not caught by the event handler (CapsLock is caught, though, but not as a standalone event), at least on my machine(s). Also, in fact, I wanted among other things to check the state of NumLock on application start, prior to any keystroke. Thanks anyway, maybe I'll take a closer look at the source code. Laurent <div class="gmail_quote"> On Mon, Oct 15, 2012 at 4:45 PM, Danny Yoo <<a href="mailto:dyoo@hashcollision.org" target="_blank">dyoo@hashcollision.org</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Oh, I forgot about allowing the subclass to process the events too! Add the following to the end of the on-subwindow-char method: (super on-subwindow-char receiver key-event) Full source code is here: <a href="https://gist.github.com/3892860" target="_blank">https://gist.github.com/3892860</a> </blockquote></div>