LightDM - Apr 2021 - lightdm --test-mode starts, but cant interact

I am trying to use lightdm test-mode to develop a modified greeter.  However,
when I type in "lightdm --test-mode --debug" at the terminal, I get
the expected X window with the greeter in it, but I'm unable to interact
with it in any way, even when I use CTRL+SHIFT to force the window to grab the
keyboard and mouse.  Nothing in the debug info suggests (to me) a reason that
the keyboard and mouse input shouldn't work.

I'm using lightdm 1.30.0 on Linux Mint 20.1.  I can provide other relevant
info as needed.

Thanks,

jonbitzen

-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<https://lists.freedesktop.org/archives/lightdm/attachments/20210416/a29b9523/attachment.htm>

> I am trying to use lightdm test-mode to develop a modified greeter.
> However, when I type in "lightdm --test-mode --debug" at the
> terminal, I get the expected X window with the greeter in it, but I'm
> unable to interact with it in any way, even when I use CTRL+SHIFT to
> force the window to grab the keyboard and mouse.  Nothing in the
> debug info suggests (to me) a reason that the keyboard and mouse
> input shouldn't work.
This sounds like an Xorg issue.  Have you looked at your Xorg logs to
confirm that it's picking up the correct input devices?

The man page says --test-mode skips things that need root privileges,
which could include things like opening input devices which your normal
user may not have access to.  Can you run lightdm as root without
--test-mode to see if it makes a difference?

Cheers,
Adam.