diff --git a/app/dialogs/resolution-calibrate-dialog.c b/app/dialogs/resolution-calibrate-dialog.c
index 6e4d4810bf..cbaf418265 100644
--- a/app/dialogs/resolution-calibrate-dialog.c
+++ b/app/dialogs/resolution-calibrate-dialog.c
@@ -84,7 +84,7 @@ resolution_calibrate_dialog (GtkWidget *resolution_entry,
 
   screen = gtk_widget_get_screen (dialog);
   monitor = gdk_screen_get_monitor_at_window (screen,
-                                              resolution_entry->window);
+                                              gtk_widget_get_window (resolution_entry));
   gdk_screen_get_monitor_geometry (screen, monitor, &rect);
 
   ruler_width  = rect.width  - 300 - (rect.width  % 100);