--- a/QScintilla/Shell.py	Sun Nov 19 13:06:01 2017 +0100
+++ b/QScintilla/Shell.py	Sat Dec 02 12:40:22 2017 +0100
@@ -1603,7 +1603,8 @@
                     self.__setHistoryIndex(index=-1)
                 elif self.__historyStyle == ShellHistoryStyle.WindowsStyle:
                     if historyIndex is None:
-                        if cmd != self.__history[self.__histidx - 1]:
+                        if bool(self.__histidx - 1) and \
+                           cmd != self.__history[self.__histidx - 1]:
                             self.__setHistoryIndex(index=-1)
                     else:
                         self.__setHistoryIndex(historyIndex)