diff --git a/user.js b/user.js
index 2cef069..a454c38 100644
--- a/user.js
+++ b/user.js
@@ -151,6 +151,7 @@ user_pref("browser.urlbar.showSearchSuggestionsFirst", false);
 user_pref("browser.urlbar.suggest.topsites", false);
 user_pref("devtools.debugger.remote-enabled", false);
 user_pref("devtools.debugger.skip-pausing", true);
+user_pref("extensions.activeThemeID", "default-theme@mozilla.org");
 user_pref("extensions.formautofill.creditCards.available", false);
 user_pref("extensions.formautofill.creditCards.enabled", false);
 user_pref("findbar.highlightAll", true);