--- src/org/openide/actions/SaveAllAction.java	
+++ src/org/openide/actions/SaveAllAction.java	
@@ -42,9 +42,13 @@ 
 package org.openide.actions;
 
 
+import java.awt.Component;
+import javax.swing.Action;
+import javax.swing.JButton;
 import javax.swing.event.ChangeEvent;
 import javax.swing.event.ChangeListener;
 import org.openide.LifecycleManager;
+import org.openide.awt.Actions;
 import org.openide.loaders.DataObject;
 import org.openide.util.Exceptions;
 import org.openide.util.HelpCtx;
@@ -77,6 +81,9 @@ 
         super.initialize ();
         // false by default
         putProperty (PROP_ENABLED, Boolean.FALSE);
+        // default tooltip  warning about CoS feature #148977
+        putValue(Action.SHORT_DESCRIPTION, NbBundle.getMessage(
+             org.openide.loaders.DataObject.class, "HINT_SaveAll"));
         // listen to the changes
         chl = new ModifiedListL();
         DataObject.getRegistry().addChangeListener(
--- src/org/openide/loaders/Bundle.properties	
+++ src/org/openide/loaders/Bundle.properties	
@@ -266,6 +266,7 @@ 
 CTL_SaveAsTemplate=&Select the category in which the new template will appear:
 CTL_SaveAsTemplate_TemplatesRoot=Templates
 SaveAll=Save &All
+HINT_SaveAll=Save all unsaved files and compile them if Compile on Save feature is on
 # FileSystemRefreshAction
 LAB_Refresh=Refresh Folder
 # NewTemplateAction