diff --git a/vncviewer/Viewport.cxx b/vncviewer/Viewport.cxx
index 1bc0b82..a12f783 100644
--- a/vncviewer/Viewport.cxx
+++ b/vncviewer/Viewport.cxx
@@ -403,8 +403,10 @@
 
   assert(self);
 
+#if !defined(WIN32) && !defined(__APPLE__)
   if (!sendPrimary && (source == 0))
     return;
+#endif
 
   Fl::paste(*self, source);
 }