diff --git a/platform/platform-api/src/com/intellij/openapi/util/BusyObject.java b/platform/platform-api/src/com/intellij/openapi/util/BusyObject.java
index d7a6499d2e3e..2849a09e1812 100644
--- a/platform/platform-api/src/com/intellij/openapi/util/BusyObject.java
+++ b/platform/platform-api/src/com/intellij/openapi/util/BusyObject.java
@@ -32,7 +32,9 @@ public interface BusyObject {
     public final void onReady() {
       ActionCallback[] ready = getReadyCallbacks(true);
       for (ActionCallback each : ready) {
-        each.setDone();
+        if (each != null) {
+          each.setDone();
+        }
       }
     }