diff --git a/src/shell-window-tracker.c b/src/shell-window-tracker.c
index 2b8220129..512f7ec1e 100644
--- a/src/shell-window-tracker.c
+++ b/src/shell-window-tracker.c
@@ -507,7 +507,7 @@ disassociate_window (ShellWindowTracker   *self,
   g_hash_table_remove (self->window_to_app, window);
 
   _shell_app_remove_window (app, window);
-  g_signal_handlers_disconnect_by_func (window, G_CALLBACK(on_wm_class_changed), self);
+  g_signal_handlers_disconnect_by_func (window, G_CALLBACK (on_wm_class_changed), self);
 
   g_signal_emit (self, signals[TRACKED_WINDOWS_CHANGED], 0);