diff -ruN mutter-3.26.1.orig/src/wayland/meta-window-wayland.c mutter-3.26.1/src/wayland/meta-window-wayland.c
--- mutter-3.26.1.orig/src/wayland/meta-window-wayland.c	2017-10-10 19:30:21.802833519 +0200
+++ mutter-3.26.1/src/wayland/meta-window-wayland.c	2017-10-10 19:31:50.368263289 +0200
@@ -69,6 +69,8 @@
 {
   if (meta_is_stage_views_scaled ())
     return 1;
+  if (logical_monitor == NULL)
+    return 1;
   else
     return meta_logical_monitor_get_scale (logical_monitor);
 }
