diff --git a/gtk/gtkthemingengine.c b/gtk/gtkthemingengine.c
index bac646bdcb..8eb5556715 100644
--- a/gtk/gtkthemingengine.c
+++ b/gtk/gtkthemingengine.c
@@ -3003,8 +3003,7 @@ gtk_theming_engine_render_activity (GtkThemingEngine *engine,
           gint inset = 0.7 * radius;
 
           /* transparency is a function of time and intial value */
-          gdouble t = 1.0 - (gdouble) ((i + num_steps - step)
-                                       % num_steps) / num_steps;
+          gdouble t = 1.0 - (gdouble) ((i + step) % num_steps) / num_steps;
           gdouble xscale = cos (i * G_PI / half);
           gdouble yscale = sin (i * G_PI / half);