diff --git a/platform/platform-impl/src/com/intellij/openapi/ui/WindowWrapperBuilder.java b/platform/platform-impl/src/com/intellij/openapi/ui/WindowWrapperBuilder.java
index ae5d7eb964be..9a8f2fd35fd8 100644
--- a/platform/platform-impl/src/com/intellij/openapi/ui/WindowWrapperBuilder.java
+++ b/platform/platform-impl/src/com/intellij/openapi/ui/WindowWrapperBuilder.java
@@ -66,7 +66,7 @@ public class WindowWrapperBuilder {
   }
 
   @NotNull
-  public WindowWrapperBuilder setDimensionServiceKey(@Nullable String dimensionServiceKey) {
+  public WindowWrapperBuilder setDimensionServiceKey(@Nullable @NonNls String dimensionServiceKey) {
     myDimensionServiceKey = dimensionServiceKey;
     return this;
   }