diff --git a/src/main/java/org/gcube/portlets/widgets/workspaceuploader/client/uploader/dragdrop/MultipleDNDUpload.java b/src/main/java/org/gcube/portlets/widgets/workspaceuploader/client/uploader/dragdrop/MultipleDNDUpload.java
index 1197d36..9947faa 100644
--- a/src/main/java/org/gcube/portlets/widgets/workspaceuploader/client/uploader/dragdrop/MultipleDNDUpload.java
+++ b/src/main/java/org/gcube/portlets/widgets/workspaceuploader/client/uploader/dragdrop/MultipleDNDUpload.java
@@ -25,16 +25,10 @@ import com.google.gwt.user.client.ui.Widget;
  * The Class MultipleDNDUpload.
  *
  * @author Francesco Mangiacrapa francesco.mangiacrapa@isti.cnr.it
- * Oct 28, 2015
+ * May 18, 2016
  */
-public class MultipleDNDUpload extends LayoutPanel implements
-		HasWorskpaceUploadNotificationListener {
+public class MultipleDNDUpload extends LayoutPanel implements HasWorskpaceUploadNotificationListener {
 
-	/**
-	 *
-	 */
-
-	// private WorkspaceFieldsUploadManager fields;
 	private String idFolder;
 	private UPLOAD_TYPE type;
 
@@ -64,11 +58,11 @@ public class MultipleDNDUpload extends LayoutPanel implements
 	public static final String DROP_TARGET_UNIQUE_CHILD_ID = "drop_target_unique_child";
 
 	/** The drop target ids. */
-	private int randomInt = Random.nextInt() + Random.nextInt();
-	private String dropTargetID = DROP_TARGET_CLASS +"-" + randomInt;
-	private String dropTargetOuterID = DROP_TARGET_OUTER_CLASS +"-"+ randomInt;
-	private String dropTargetInnerID = DROP_TARGET_INNER_CLASS +"-"+ randomInt;
-	private String dropTargetUniqueChildID = DROP_TARGET_UNIQUE_CHILD_ID +"-"+ randomInt;
+	private String randomID = Random.nextInt() + "_" +Random.nextInt();
+	private String dropTargetID = DROP_TARGET_CLASS +"-" + randomID;
+	private String dropTargetOuterID = DROP_TARGET_OUTER_CLASS +"-"+ randomID;
+	private String dropTargetInnerID = DROP_TARGET_INNER_CLASS +"-"+ randomID;
+	private String dropTargetUniqueChildID = DROP_TARGET_UNIQUE_CHILD_ID +"-"+ randomID;
 
 	/**
 	 * Instantiates a new DND file reader.
@@ -304,6 +298,8 @@ public class MultipleDNDUpload extends LayoutPanel implements
 	}
 
 	/**
+	 * Gets the drop target id.
+	 *
 	 * @return the dropTargetID
 	 */
 	public String getDropTargetID() {
@@ -312,6 +308,8 @@ public class MultipleDNDUpload extends LayoutPanel implements
 	}
 
 	/**
+	 * Gets the drop target outer id.
+	 *
 	 * @return the dropTargetOuterID
 	 */
 	public String getDropTargetOuterID() {
@@ -321,6 +319,8 @@ public class MultipleDNDUpload extends LayoutPanel implements
 
 
 	/**
+	 * Gets the drop target inner id.
+	 *
 	 * @return the dropTargetInnerID
 	 */
 	public String getDropTargetInnerID() {
@@ -337,7 +337,8 @@ public class MultipleDNDUpload extends LayoutPanel implements
 	private static native void resetPanel(MultipleDNDUpload instance) /*-{
 		var drop_target_inner = instance.@org.gcube.portlets.widgets.workspaceuploader.client.uploader.dragdrop.MultipleDNDUpload::dropTargetInnerID;
 		var drop_target_outer = instance.@org.gcube.portlets.widgets.workspaceuploader.client.uploader.dragdrop.MultipleDNDUpload::dropTargetOuterID;
-		var drop = $wnd.$('#drop_target')[0];
+		var drop_target = instance.@org.gcube.portlets.widgets.workspaceuploader.client.uploader.dragdrop.MultipleDNDUpload::dropTargetID;
+		var drop = $wnd.$('#'+drop_target)[0];
 		if (drop === null || drop === undefined) {
 			return;
 		}