gistfile1.diff

diff -r 23f5c4975e67 common/content/tabs.js
--- a/common/content/tabs.js	Mon Jun 13 20:33:33 2011 +0200
+++ b/common/content/tabs.js	Fri Jun 17 14:28:38 2011 +0900
@@ -595,7 +595,9 @@
         else
             return -1;
 
-        if (position > last)
+        if (length == 1)
+            position = 0;
+        else if (position > last)
             position = wrap ? position % length : last;
         else if (position < 0)
             position = wrap ? (position % length) + length : 0;