diff --git a/testcases/t/10-dock.t b/testcases/t/10-dock.t
index 97ac5f41..b1b7bfcb 100644
--- a/testcases/t/10-dock.t
+++ b/testcases/t/10-dock.t
@@ -43,4 +43,17 @@ sleep 0.25;
 my $rect = $window->rect;
 is($rect->width, $primary->rect->width, 'dock client is as wide as the screen');
 
+my $fwindow = $x->root->create_child(
+    class => WINDOW_CLASS_INPUT_OUTPUT,
+    rect => [ 0, 0, 30, 30],
+    background_color => '#FF0000',
+    type => $x->atom(name => '_NET_WM_WINDOW_TYPE_DOCK'),
+);
+
+$fwindow->transient_for($window);
+$fwindow->map;
+
+sleep 0.25;
+
+
 diag( "Testing i3, Perl $], $^X" );