diff --git a/mozilla/widget/src/gtk/nsGtkEventHandler.cpp b/mozilla/widget/src/gtk/nsGtkEventHandler.cpp
index f7220b22a36..9e96841bee0 100644
--- a/mozilla/widget/src/gtk/nsGtkEventHandler.cpp
+++ b/mozilla/widget/src/gtk/nsGtkEventHandler.cpp
@@ -50,6 +50,7 @@ struct nsKeyConverter nsKeycodes[] = {
   { NS_VK_CANCEL,     GDK_Cancel },
   { NS_VK_BACK,       GDK_BackSpace },
   { NS_VK_TAB,        GDK_Tab },
+  { NS_VK_TAB,        GDK_ISO_Left_Tab },
   { NS_VK_CLEAR,      GDK_Clear },
   { NS_VK_RETURN,     GDK_Return },
   { NS_VK_SHIFT,      GDK_Shift_L },
diff --git a/mozilla/widget/src/xlib/nsKeyCode.cpp b/mozilla/widget/src/xlib/nsKeyCode.cpp
index fa1147743bc..ec24ac9dfdb 100644
--- a/mozilla/widget/src/xlib/nsKeyCode.cpp
+++ b/mozilla/widget/src/xlib/nsKeyCode.cpp
@@ -36,6 +36,7 @@ struct nsKeyConverter nsKeycodes[] =
   { NS_VK_CANCEL,        XK_Cancel},
   { NS_VK_BACK,          XK_BackSpace},
   { NS_VK_TAB,           XK_Tab},
+  { NS_VK_TAB,           XK_ISO_Left_Tab },    
   { NS_VK_CLEAR,         XK_Clear},
   { NS_VK_RETURN,        XK_Return},
   { NS_VK_ENTER,         XK_KP_Enter},