--- a/browser/app/profile/firefox.js
+++ b/browser/app/profile/firefox.js
@@ -1327,16 +1327,18 @@ pref("services.sync.prefs.sync.signon.re
 pref("services.sync.prefs.sync.spellchecker.dictionary", true);
 pref("services.sync.prefs.sync.xpinstall.whitelist.required", true);
 #endif
 
 // Developer edition preferences
 #ifdef MOZ_DEV_EDITION
 sticky_pref("lightweightThemes.selectedThemeID", "firefox-devedition@mozilla.org");
 sticky_pref("browser.devedition.theme.enabled", true);
+#else
+sticky_pref("lightweightThemes.selectedThemeID", "");
 #endif
 
 // Developer edition promo preferences
 pref("devtools.devedition.promo.shown", false);
 pref("devtools.devedition.promo.url", "https://www.mozilla.org/firefox/developer/?utm_source=firefox-dev-tools&utm_medium=firefox-browser&utm_content=betadoorhanger");
 
 // Only potentially show in beta release
 #if MOZ_UPDATE_CHANNEL == beta

--- a/browser/components/customizableui/test/browser_1007336_lwthemes_in_customize_mode.js
+++ b/browser/components/customizableui/test/browser_1007336_lwthemes_in_customize_mode.js
@@ -46,17 +46,17 @@ add_task(function () {
   ok(installedThemeId.startsWith(firstLWThemeId),
      "The second theme in the 'My Themes' section should be the newly installed theme: " +
      "Installed theme id: " + installedThemeId + "; First theme ID: " + firstLWThemeId);
   is(header.nextSibling.nextSibling.nextSibling, recommendedHeader,
      "There should be two themes in the 'My Themes' section");
 
   let defaultTheme = header.nextSibling;
   defaultTheme.doCommand();
-  is(Services.prefs.prefHasUserValue("lightweightThemes.selectedThemeID"), false, "No lwtheme should be selected");
+  is(Services.prefs.getCharPref("lightweightThemes.selectedThemeID"), "", "No lwtheme should be selected");
 });
 
 add_task(function asyncCleanup() {
   yield endCustomizing();
 
   Services.prefs.clearUserPref("lightweightThemes.usedThemes");
   Services.prefs.clearUserPref("lightweightThemes.recommendedThemes");
 })
\ No newline at end of file

--- a/toolkit/mozapps/extensions/LightweightThemeManager.jsm
+++ b/toolkit/mozapps/extensions/LightweightThemeManager.jsm
@@ -297,17 +297,17 @@ this.LightweightThemeManager = {
           _notifyWindows(this.currentThemeForDisplay);
         }.bind(this));
       }
     }
 
     if (aData)
       _prefs.setCharPref("selectedThemeID", aData.id);
     else
-      _prefs.deleteBranch("selectedThemeID");
+      _prefs.setCharPref("selectedThemeID", "");
 
     _notifyWindows(aData);
     Services.obs.notifyObservers(null, "lightweight-theme-changed", null);
   },
 
   /**
    * Starts the Addons provider and enables the new lightweight theme if
    * necessary.