LightDM currently assigns each seat a different VT, and each seat tries to switch to its own VT when starting X. If I understand correctly, these switches compete with each other, causing the problem.
The proper solution is to have only the primary seat switch VTs, then have all other seats share that VT. LightDM doesn't currently support this, but I have some changes to LightDM in progress to add more complete multiseat support. If you are using Ubuntu, please try installing the version of LightDM in my PPA (<https://launchpad.net/~a7x/+archive/multiseat>):
LightDM currently assigns each seat a different VT, and each seat tries to switch to its own VT when starting X. If I understand correctly, these switches compete with each other, causing the problem.
The proper solution is to have only the primary seat switch VTs, then have all other seats share that VT. LightDM doesn't currently support this, but I have some changes to LightDM in progress to add more complete multiseat support. If you are using Ubuntu, please try installing the version of LightDM in my PPA (<https:/ /launchpad. net/~a7x/ +archive/ multiseat>):
sudo apt-add-repository ppa:a7x/multiseat
sudo apt-get update
sudo apt-get upgrade
More complete instructions can be found by visiting the PPA page.