From ba75141e4b40a8a32c129169595368d82d139331 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Mon, 4 Mar 2013 11:20:48 +0530
Subject: [PATCH] ...

---
 src/calibre/gui2/actions/__init__.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/calibre/gui2/actions/__init__.py b/src/calibre/gui2/actions/__init__.py
index 497b23c080..3b00a127d0 100644
--- a/src/calibre/gui2/actions/__init__.py
+++ b/src/calibre/gui2/actions/__init__.py
@@ -129,7 +129,9 @@ class InterfaceAction(QObject):
         ''' This method should perform some useful action and return True
         iff this interface action is capable of handling the drag event. Do not
         call accept/ignore on the event, that will be taken care of by the
-        calibre UI.'''
+        calibre UI. You should not perform blocking/long operations in this
+        function. Instead emit a signal or use QTimer.singleShot and return
+        quickly. See the builtin actions for examples.'''
         return False
 
     def do_genesis(self):