diff --git a/src/browser/components/preferences/zen-settings.js b/src/browser/components/preferences/zen-settings.js
index c782fa145..6752fc435 100644
--- a/src/browser/components/preferences/zen-settings.js
+++ b/src/browser/components/preferences/zen-settings.js
@@ -736,6 +736,7 @@ var gZenWorkspacesSettings = {
     Services.prefs.addObserver("zen.glance.enabled", tabsUnloaderPrefListener); // We can use the same listener for both prefs
     Services.prefs.addObserver("zen.workspaces.separate-essentials", tabsUnloaderPrefListener);
     Services.prefs.addObserver("zen.glance.activation-method", tabsUnloaderPrefListener);
+    Services.prefs.addObserver("zen.window-sync.sync-only-pinned-tabs", tabsUnloaderPrefListener);
     Services.prefs.addObserver(
       "zen.tabs.ctrl-tab.ignore-essential-tabs",
       toggleZenCycleByAttrWarning
@@ -745,6 +746,7 @@ var gZenWorkspacesSettings = {
       Services.prefs.removeObserver("zen.glance.enabled", tabsUnloaderPrefListener);
       Services.prefs.removeObserver("zen.glance.activation-method", tabsUnloaderPrefListener);
       Services.prefs.removeObserver("zen.workspaces.separate-essentials", tabsUnloaderPrefListener);
+      Services.prefs.removeObserver("zen.window-sync.sync-only-pinned-tabs", tabsUnloaderPrefListener);
       Services.prefs.removeObserver(
         "zen.tabs.ctrl-tab.ignore-essential-tabs",
         toggleZenCycleByAttrWarning