FVWM: Which setting to give focus to a window that just popped up?

Hello,

I am the maintainer of the Slint distribution:
http://slint.fr
http://slackware.uk/slint/x86_64/slint-testing/

This distribution includes, among others WMs/DEs, as standalone FVWM
2.6.7 window manager associated to lxpanel, and also a LXDE desktop with
FVWM 2.6.7 instead of Openbox as window manager.

The upcoming version 14.2.1 will be accessible to visually impaired
users in graphical environments through text to speech and/or a braille
device, using mainly the brltty and Orca software.

Actually we have two config files, ~/.fvwm/config.others and
~/.fwmm/config.lxde, ~/.fvwm/config being used to choose which one to
use, with ust theses two lines:
Test (EnvMatch DESKTOP_SESSION LXDE) Read config.lxde
Test (!EnvMatch DESKTOP_SESSION LXDE) Read config.others

After preliminary tests, I received this feedback from a blind user (in
CC):

> - LXDE, FVWM and TWM have problems giving focus to the opened windows.
> When I start programs like Pluma or Wm-logout for example, I get the
> message, "GTK Accessibility Module initialized," but the programs'
> windows don't get focus and I'm unable to use them.

So, she would like that when she types a command that creates a window,
or select an application menu entry (e.g. from the application menu
plugged in lxpanel), this window be always given the focus. Some
examples of applications associated to such windows:
- a logout dialog
- a run dialog
- firefox or thunderbird
- geany or pluma

Of course the application itself has to be accessible, this not the
point here.

I have read the man page an especially the options of the style command
to find how I could always give the focus to the a window what just
popped up, including what is written under:
Grabbing the focus when a new window is created [1]

But didn't find the right commands to get this result.

Of course in this context moving the mouse above a window or clicking in
it is not realistic, so I am looking for a solution that does not need
to use a mouse.

Any clue appreciated.

Best,

Didier

[1] English is not my native language, so it may just be that I don't
understand the options.