Prevent replacing the default policy

Author: aaronkollasch

src/ui/options.js

@@ -223,6 +223,11 @@ document.querySelector("#version").textContent = _("Version",
 
   async function copyContainer() {
     cookieStoreId = containerSelect.value;
+    if (cookieStoreId == "default") {
+      alert("Cannot replace the default policy.")
+      containerCopy.value = "blank";
+      return;
+    }
     let copyCookieStoreId = containerCopy.value;
     let copyContainerName = containerCopy.options[containerCopy.selectedIndex].text;
     let copyPolicy = await UI.getPolicy(copyCookieStoreId);