Menu `SendMessage` actions not working on OpenBSD 6.4

[morgant]

In the development various MLVWM styles for various applications as part of mlvwmrc, I can't seem to get Menu SendMessage actions (e.g. Menu "Open Location..." Action SendMessage C+G which should send a Control-G keypress to the active window) to function. I'm currently testing on OpenBSD 6.4.

I've even configured a style for xev (the X Windows event tester) and can confirm that a KeyPress is being sent. My current observations:

• sendevent() in functions.c only fires a single 'KeyPress' XSendEvent() for each key, but doesn't send a 'KeyRelease'
• sendevent() specifies same_screen = false, while actual keypress/keyrelease events have same_screen = true (as confirmed with xev)
• When playing with xev, the KeyPress event does appear to have the correct state value (which specifies the modifier key), but maybe it'd be better to send a 'KeyPress' for the modifier, then the 'KeyPress' & 'KeyRelease' for the key, followed by a 'KeyRelease' for the modifier?
• It also sounds like several sources saying that "events send by XSendEvent() (those send_event flag in Event struct were set) may ignored by some clients", see http://t-sato.in.coocan.jp/xvkbd/events.html

[morgant]

Interestingly, "Open Location..." Action SendMessage C+L works for Chromium/chrome under OpenBSD 6.4, so I'm not sure if it was just the other browser I was testing that wasn't working.

[morgant]

I'm not sure if I was accidentally preceding the line with "Menu" or what, but SendMessage has been working through OpenBSD 6.5 & 6.6. That said, it can sometimes be inconsistent in the window/application receiving it.

One thing I've discovered is if you want to send a key press without a modifier key, one must precede it with N+ (no modifier), e.g. "Next" Action SendMessage N+P.

[morgant]

Re-opening this as @pierre-rs pointed out that SendMessage is not working for ARandR under a number of OSes. I've confirmed under OpenBSD amd64/7.3-stable.

[morgant]

In experimenting with xvkbd under OpenBSD amd64/7.5-stable, I read the following passage in the manual:

     -xsendevent
         Make xvkbd to use XSendEvent() to simulate keyboard events, as it was
         in xvkbd version 1.0.  xvkbd version 1.1 and later will try to use
         XTEST extension instead in the default configuration.  Because it is
         not unusual applications to ignore keyboard events generated with
         -xsendevent, you shouldn't use -xsendevent option unless it is really
         required.
         If XTEST extension is not supported by the X server, xvkbd will
         automatically switch to this mode.
         Resource `xvkbd.xtest: false' has the same function.

It immediately made me think of this issue as mlvwm is still using XSendEvent, not the XTEST X11 extension. (Of course, I had completely forgotten that I had already referenced xvkbd documentation in this issue!) So, I should really start by addressing this by using XTEST (see the xtest1(3) manual), when available.