diff --git a/res/values/strings.xml b/res/values/strings.xml
index f833dc798..320047493 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -60,7 +60,8 @@
     <string name="send_alternate_chooser_title">Choose sender</string>
       
     <string name="mark_all_as_read_dlg_title">Mark all messages as read</string>
-    <string name="mark_all_as_read_dlg_instructions_fmt">Mark all messages in \'<xliff:g id="folder">%s</xliff:g>\' as read?</string>
+    <string name="mark_all_as_read_dlg_instructions_fmt">Mark all messages in \'<xliff:g id="folder">%s</xliff:g>\' as read?  (including
+    messages in the folder that are not displayed in K-9)</string>
   
     <string name="flag_action">Flag</string>
     <string name="unflag_action">Unflag</string>