diff --git a/core/src/main/java/hudson/model/CauseAction.java b/core/src/main/java/hudson/model/CauseAction.java
index 356d7d7ee6..2835aa1d9e 100644
--- a/core/src/main/java/hudson/model/CauseAction.java
+++ b/core/src/main/java/hudson/model/CauseAction.java
@@ -24,13 +24,13 @@
 package hudson.model;
 
 import hudson.model.Queue.Task;
+import hudson.model.queue.FoldableAction;
+import org.kohsuke.stapler.export.Exported;
+import org.kohsuke.stapler.export.ExportedBean;
 
 import java.util.ArrayList;
 import java.util.List;
 
-import org.kohsuke.stapler.export.Exported;
-import org.kohsuke.stapler.export.ExportedBean;
-
 @ExportedBean
 public class CauseAction implements FoldableAction {
     /**
@@ -77,15 +77,14 @@ public class CauseAction implements FoldableAction {
         return causes.get(0).getShortDescription();
     }
 
-	public void foldIntoExisting(Task t, List<Action> actions) {
-		for(Action action : actions) {
-			if(action instanceof CauseAction) {
-				this.causes.addAll(((CauseAction)action).causes);
-				return;
-			}
+    public void foldIntoExisting(hudson.model.Queue.Item item, Task owner, List<Action> otherActions) {
+        CauseAction existing = item.getAction(CauseAction.class);
+        if (existing!=null) {
+            existing.causes.addAll(this.causes);
+            return;
 		}
 		// no CauseAction found, so add a copy of this one
-		actions.add(new CauseAction(this));
+		item.getActions().add(new CauseAction(this));
 	}
 	
 	private Object readResolve() {
diff --git a/core/src/main/java/hudson/model/Queue.java b/core/src/main/java/hudson/model/Queue.java
index e03e77abc9..b784edc961 100644
--- a/core/src/main/java/hudson/model/Queue.java
+++ b/core/src/main/java/hudson/model/Queue.java
@@ -380,7 +380,7 @@ public class Queue extends ResourceController implements Saveable {
 
         return scheduleInternal(p, quietPeriod, actions);
     }
-    
+
     /**
      * Schedules an execution of a task.
      *
@@ -426,7 +426,7 @@ public class Queue extends ResourceController implements Saveable {
         // but let the actions affect the existing stuff.
         for(Item item : duplicatesInQueue) {
             for(FoldableAction a : Util.filter(actions,FoldableAction.class)) {
-                a.foldIntoExisting(item.task, item.getActions());
+                a.foldIntoExisting(item, p, actions);
             }
         }
 
@@ -1207,6 +1207,8 @@ public class Queue extends ResourceController implements Saveable {
     /**
      * An optional interface for actions on Queue.Item.
      * Lets the action cooperate in queue management.
+     * 
+     * @since 1.300-ish.
      */
     public interface QueueAction extends Action {
     	/**
diff --git a/core/src/main/java/hudson/model/FoldableAction.java b/core/src/main/java/hudson/model/queue/FoldableAction.java
similarity index 56%
rename from core/src/main/java/hudson/model/FoldableAction.java
rename to core/src/main/java/hudson/model/queue/FoldableAction.java
index 6e822fab97..f8f6e7bc08 100644
--- a/core/src/main/java/hudson/model/FoldableAction.java
+++ b/core/src/main/java/hudson/model/queue/FoldableAction.java
@@ -21,18 +21,39 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
-package hudson.model;
+package hudson.model.queue;
 
 import hudson.model.Queue.Task;
+import hudson.model.Action;
+import hudson.model.Queue;
 
 import java.util.List;
 
 /**
- * @author mdonohue
  * An action interface that allows action data to be folded together.
- * This is useful for combining any distinct values from a build determined to 
- * be a duplicate of a build already in the build queue.
+ *
+ * <p>
+ * {@link Action} can implement this optional marker interface to be notified when
+ * the {@link Task} that it's added to the queue with is determined to be "already in the queue".
+ *
+ * <p>
+ * This is useful for passing on parameters to the task that's already in the queue.
+ *
+ * @author mdonohue
+ * @since 1.300-ish.
  */
 public interface FoldableAction extends Action {
-    public void foldIntoExisting(Task t, List<Action> actions);
+    /**
+     * Notifies that the {@link Task} that "owns" this action (that is, the task for which this action is submitted)
+     * is considered as a duplicate.
+     *
+     * @param item
+     *      The existing {@link Queue.Item} in the queue against which we are judged as a duplicate. Never null.
+     * @param owner
+     *      The {@link Task} with which this action was submitted to the queue. Never null.
+     * @param otherActions
+     *      Other {@link Action}s that are submitted with the task. (One of them is this {@link FoldableAction}.)
+     *      Never null.
+     */
+    void foldIntoExisting(Queue.Item item, Task owner, List<Action> otherActions);
 }