diff --git a/platform/util/src/com/intellij/util/ui/UIUtil.java b/platform/util/src/com/intellij/util/ui/UIUtil.java
index 4e824b1bc2ea..b950b0b29332 100644
--- a/platform/util/src/com/intellij/util/ui/UIUtil.java
+++ b/platform/util/src/com/intellij/util/ui/UIUtil.java
@@ -3425,7 +3425,9 @@ public class UIUtil {
 
   /**
    * Returns the first focusable component in the specified container.
-   * This method works.
+   * This method returns {@code null} if container is {@code null},
+   * or if focus traversal policy cannot be determined,
+   * or if found focusable component is not a {@link JComponent}.
    *
    * @param container a container whose first focusable component is to be returned
    * @return the first focusable component or {@code null} if it cannot be found