diff --git a/jme3-core/src/main/java/com/jme3/anim/tween/action/BaseAction.java b/jme3-core/src/main/java/com/jme3/anim/tween/action/BaseAction.java
index df67153fc6..edc819f7ff 100644
--- a/jme3-core/src/main/java/com/jme3/anim/tween/action/BaseAction.java
+++ b/jme3-core/src/main/java/com/jme3/anim/tween/action/BaseAction.java
@@ -103,7 +103,7 @@ public void setMaskPropagationEnabled(boolean maskPropagationEnabled) {
      * the mask attribute will not affect the actions under this base action. Setting this to 'null' will animate
      * the entire model.
      *
-     * @param mask an animation mask to be applied to this action.
+     * @param mask an animation mask to be applied to this action (nullable).
      * @see com.jme3.anim.AnimLayer to adjust the animation mask to control which part will be animated
      * @see BaseAction#setMaskPropagationEnabled(boolean)
      */