diff --git a/src/calibre/gui2/viewer/gestures.py b/src/calibre/gui2/viewer/gestures.py
index 2aee47710d..32a6ea6d1b 100644
--- a/src/calibre/gui2/viewer/gestures.py
+++ b/src/calibre/gui2/viewer/gestures.py
@@ -6,7 +6,7 @@ from __future__ import (unicode_literals, division, absolute_import,
 __license__ = 'GPL v3'
 __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import time, ctypes, sys
+import time, sys
 from functools import partial
 from PyQt5.Qt import (
     QObject, QPointF, pyqtSignal, QEvent, QApplication, QMouseEvent, Qt,
@@ -16,7 +16,6 @@ from calibre.constants import iswindows
 
 touch_supported = False
 if iswindows and sys.getwindowsversion()[:2] >= (6, 2):  # At least windows 7
-    from ctypes import wintypes
     touch_supported = True
 
 SWIPE_HOLD_INTERVAL = 0.5  # seconds
@@ -263,34 +262,14 @@ class GestureHandler(QObject):
         self.state.pinched.connect(self.handle_pinch)
         self.evmap = {QEvent.TouchBegin: 'start', QEvent.TouchUpdate: 'update', QEvent.TouchEnd: 'end'}
 
-        # Ignore fake mouse events generated by the window system from touch
-        # events. At least on windows, we know how to identify these fake
-        # events. See http://msdn.microsoft.com/en-us/library/windows/desktop/ms703320(v=vs.85).aspx
-        self.is_fake_mouse_event = lambda : False
-        if touch_supported and iswindows:
-            MI_WP_SIGNATURE = 0xFF515700
-            SIGNATURE_MASK = 0xFFFFFF00
-            try:
-                f = ctypes.windll.user32.GetMessageExtraInfo
-                f.restype = wintypes.LPARAM
-                def is_fake_mouse_event():
-                    val = f()
-                    ans = (val & SIGNATURE_MASK) == MI_WP_SIGNATURE
-                    return ans
-                self.is_fake_mouse_event = is_fake_mouse_event
-            except Exception:
-                import traceback
-                traceback.print_exc()
-
     def __call__(self, ev):
         if not touch_supported:
             return False
         etype = ev.type()
         if etype in (
                 QEvent.MouseMove, QEvent.MouseButtonPress,
-                QEvent.MouseButtonRelease, QEvent.MouseButtonDblClick,
-                QEvent.ContextMenu) and self.is_fake_mouse_event():
-            # swallow fake mouse events that the windowing system generates from touch events
+                QEvent.MouseButtonRelease, QEvent.MouseButtonDblClick) and ev.source() != Qt.MouseEventNotSynthesized:
+            # swallow fake mouse events generated from touch events
             ev.accept()
             return True
         boundary = self.evmap.get(etype, None)