=== modified file 'src/libnrtype/Layout-TNG.h'                                                                                                                                                                    
--- src/libnrtype/Layout-TNG.h  2014-11-10 17:39:33 +0000                                                                                                                                                         
+++ src/libnrtype/Layout-TNG.h	2014-12-18 01:05:08 +0000
@@ -657,7 +657,10 @@
 
     /** The overall block-progression of the whole flow. */
     inline Direction _blockProgression() const
-        {return static_cast<InputStreamTextSource*>(_input_stream.front())->styleGetBlockProgression();}
+        {
+    if(_input_stream.empty())return LEFT_TO_RIGHT;
+    return static_cast<InputStreamTextSource*>(_input_stream.front())->styleGetBlockProgression();
+    }
 
     /** so that LEFT_TO_RIGHT == RIGHT_TO_LEFT but != TOP_TO_BOTTOM */
     static bool _directions_are_orthogonal(Direction d1, Direction d2);