diff --git a/mozilla/modules/libpref/src/unix/unix.js b/mozilla/modules/libpref/src/unix/unix.js
index ac1e89c596a..ba163f427d7 100644
--- a/mozilla/modules/libpref/src/unix/unix.js
+++ b/mozilla/modules/libpref/src/unix/unix.js
@@ -50,6 +50,9 @@ pref("middlemouse.scrollbarPosition", true);
 // Clipboard behavior
 pref("clipboard.autocopy", true);
 
+// keyboard Mode_switch workaround
+pref("keyboard.mode_switch.enable_workaround", true);
+
 // Most Unix people think modal pref windows are stupid:
 pref("browser.prefWindowModal", false);