diff --git a/flatland/utils/rendertools.py b/flatland/utils/rendertools.py
index 8036294b71e78039f1452ebe0603f148e8bc6772..2a0b1af88656e4ef395070381790bf55443d84d8 100644
--- a/flatland/utils/rendertools.py
+++ b/flatland/utils/rendertools.py
@@ -676,8 +676,7 @@ class RenderTool(object):
 
             if self.agentRenderVariant == AgentRenderVariant.BOX_ONLY:
                 self.gl.setCellOccupied(iAgent, *(agent.position))
-            elif self.agentRenderVariant == AgentRenderVariant.ONE_STEP_BEHIND or \
-                self.agentRenderVariant == AgentRenderVariant.ONE_STEP_BEHIND_AND_BOX:
+            elif self.agentRenderVariant == AgentRenderVariant.ONE_STEP_BEHIND or self.agentRenderVariant == AgentRenderVariant.ONE_STEP_BEHIND_AND_BOX:
                 if agent.old_position is not None:
                     position = agent.old_position
                     direction = agent.direction
diff --git a/tox.ini b/tox.ini
index 6e4223172b83be922ac0fa97f981c6ea4c48c1ea..2047166aace141680561623c7edf4d11a2b4534f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -130,6 +130,7 @@ setenv =
     PYTHONPATH = {toxinidir}
 passenv =
     DISPLAY
+    XAUTHORITY
 ; HTTP_PROXY+HTTPS_PROXY required behind corporate proxies
     HTTP_PROXY
     HTTPS_PROXY