diff --git a/appvm-scripts/usrbin/qubes-run-xephyr b/appvm-scripts/usrbin/qubes-run-xephyr
index 8e9269bf..a2849cc0 100644
--- a/appvm-scripts/usrbin/qubes-run-xephyr
+++ b/appvm-scripts/usrbin/qubes-run-xephyr
@@ -1,6 +1,6 @@
 #!/bin/sh
 DISPLAY_XEPHYR="$1"
-OPTIONS_XEPHYR="-no-host-grab -fullscreen"
+OPTIONS_XEPHYR="-no-host-grab -output DUMMY0"
 
 if [ -e /usr/lib/x86_64-linux-gnu/qubes-gui-daemon/shmoverride.so ]; then
     SHMOVERRIDE=/usr/lib/x86_64-linux-gnu/qubes-gui-daemon/shmoverride.so
diff --git a/appvm-scripts/usrbin/qubes-set-monitor-layout b/appvm-scripts/usrbin/qubes-set-monitor-layout
index b38e0cc6..3bdee8ae 100755
--- a/appvm-scripts/usrbin/qubes-set-monitor-layout
+++ b/appvm-scripts/usrbin/qubes-set-monitor-layout
@@ -4,6 +4,11 @@
 # on having DISPLAY set from there
 export DISPLAY=:0
 
+if [ -e /run/qubes-service/guivm-gui-agent ]; then
+    # on sys-gui, adjust monitor layout of the parent Xorg
+    export DISPLAY=:1
+fi
+
 # Wait for Xorg complete startup
 while ! xrandr -q &>/dev/null; do sleep 0.1; done