Daniel and Gregory,

I have had a look at this.

I can conform that slim seems to do the right thing at the AT_SPI_BUS is set and
available.

On Wed, Mar 25, 2020 at 08:06:22AM +0000, Daniel Abrecht via Dng wrote:
> Hi
>
> I've had that problem as well. It also prevents the auto-show feature of the
> `onboard` onscreen keyboard from working (which was annoying on my Librem 5
> Phone, where I need that feature).
>
> To me, it seams to be caused by a combination of something `lightdm` does,
> and something `at-spi-bus-launcher` does not do.
> After a login with `lightdm`, the X11 root window has the `AT_SPI_BUS`
> property set (`xprop -root AT_SPI_BUS`), however, it seams the
> `at-spi-bus-launcher`/`at-spi2-registryd` instance which created that
> property does not exist anymore, causing applications to fail to connect to
> it. In addition to this, the presence of that property prevents a new
> instance of `at-spi-bus-launcher`
> from starting.
>
> My current workaround is to remove the `AT_SPI_BUS` property, and then start
> `at-spi-bus-launcher` again:
> ```
> xprop -root -remove AT_SPI_BUS
> /usr/lib/at-spi2-core/at-spi-bus-launcher &
> ```

Daniel, I get the same results as you with lightdm and your workaround is good
too. Although I don't have to restart the at-spi-bus-launcher process manually,
it is started automatically once a process tries to use it.

The issue seems to be that lightdm starts its own AT_SPI_BUS which is then
killed on login. But the AT_SPI_BUS property isn't removed so that it can be
relaunched in the user's session. This is depsite Debian #760740 being marked
as fixed.

That bug also suggests another workaround of setting 'xserver-share=false' in
/etc/lightdm/lightdm.conf which also seems to work.

Mark