diff --git a/src/gui_at_sb.c b/src/gui_at_sb.c
index 659e934..1816daa 100644
--- a/src/gui_at_sb.c
+++ b/src/gui_at_sb.c
@@ -645,7 +645,11 @@
     static Boolean
 CompareEvents(XEvent *oldEvent, XEvent *newEvent)
 {
-#define Check(field) if (newEvent->field != oldEvent->field) return False;
+#define Check(field) \
+    do { \
+	if (newEvent->field != oldEvent->field) \
+	    return False; \
+    } while (0)
 
     Check(xany.display);
     Check(xany.type);