diff --git a/lib/sup/modes/thread_index_mode.rb b/lib/sup/modes/thread_index_mode.rb
index 71d3fed64..3cd116dcd 100644
--- a/lib/sup/modes/thread_index_mode.rb
+++ b/lib/sup/modes/thread_index_mode.rb
@@ -135,7 +135,16 @@ def select t=nil, when_done=nil
   end
 
   def multi_select threads
-    threads.each { |t| select t }
+    tagged_no = @tags.number_of_tagged
+    if tagged_no > 1
+    	total_msg_no = 0
+    	threads.each { |t| total_msg_no += t.size }
+    	if BufferManager.ask_yes_or_no "Are you sure, you want to open #{tagged_no} threads with #{total_msg_no} messages (y/n)?"
+    		threads.each { |t| select t }
+    	end
+    else
+    	threads.each { |t| select t }
+    end
   end
 
   ## these two methods are called by thread-view-modes when the user
diff --git a/lib/sup/tagger.rb b/lib/sup/tagger.rb
index d02b04513..a027a72f2 100644
--- a/lib/sup/tagger.rb
+++ b/lib/sup/tagger.rb
@@ -16,7 +16,8 @@ def tag o; @tagged[o] = true; end
   def untag o; @tagged[o] = false; end
   def drop_all_tags; @tagged.clear; end
   def drop_tag_for o; @tagged.delete o; end
-
+  def number_of_tagged; @tagged.select_by_value.size; end
+  
   def apply_to_tagged action=nil
     targets = @tagged.select_by_value
     num_tagged = targets.size