diff --git a/src/shell-perf-helper.c b/src/shell-perf-helper.c
index eea5d47be..e5eab208b 100644
--- a/src/shell-perf-helper.c
+++ b/src/shell-perf-helper.c
@@ -125,9 +125,10 @@ on_window_draw (GtkWidget  *window,
                 WindowInfo *info)
 {
   cairo_rectangle_int_t allocation;
-  gtk_widget_get_allocation (window, &allocation);
   double x_offset, y_offset;
 
+  gtk_widget_get_allocation (window, &allocation);
+
   /* We draw an arbitrary pattern of red lines near the border of the
    * window to make it more clear than empty windows if something
    * is drastrically wrong.