diff --git a/src/tests/test-client.c b/src/tests/test-client.c
index 2c19d9a36..8b37a4225 100644
--- a/src/tests/test-client.c
+++ b/src/tests/test-client.c
@@ -813,6 +813,32 @@ main(int argc, char **argv)
 
   gtk_init (NULL, NULL);
 
+  if (!wayland)
+    {
+      GdkScreen *screen;
+      GtkCssProvider *provider;
+
+      screen = gdk_screen_get_default ();
+      provider = gtk_css_provider_new ();
+      static const char *no_decoration_css =
+        "decoration {"
+        "  border-radius: 0 0 0 0;"
+        "  border-width: 0;"
+        "  box-shadow: 0 0 0 0 rgba(0, 0, 0, 0), 0 0 0 0 rgba(0, 0, 0, 0);"
+        "  margin: 0px;"
+        "}";
+      if (!gtk_css_provider_load_from_data (provider,
+                                            no_decoration_css,
+                                            strlen (no_decoration_css),
+                                            &error))
+        {
+          g_printerr ("%s", error->message);
+          return 1;
+        }
+      gtk_style_context_add_provider_for_screen (screen, GTK_STYLE_PROVIDER (provider),
+                                                 GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+    }
+
   windows = g_hash_table_new_full (g_str_hash, g_str_equal,
                                    g_free, NULL);
   event_source_quark = g_quark_from_static_string ("event-source");