diff --git a/src/ZenWorkspaces.mjs b/src/ZenWorkspaces.mjs
index a61762f..2146da2 100644
--- a/src/ZenWorkspaces.mjs
+++ b/src/ZenWorkspaces.mjs
@@ -740,7 +740,7 @@ var ZenWorkspaces = new (class extends ZenMultiWindowFeature {
     const parent = browser.ownerGlobal;
     let tab = gBrowser.getTabForBrowser(browser);
     let workspaceID = tab.getAttribute('zen-workspace-id');
-    if (!workspaceID) {
+    if (!workspaceID || (tab.pinned && !this._shouldAllowPinTab)) {
       return;
     }
     let activeWorkspace = await parent.ZenWorkspaces.getActiveWorkspace();