diff --git a/web/src/lib/routes.ts b/web/src/lib/routes.ts
index e62eedd..c51b687 100644
--- a/web/src/lib/routes.ts
+++ b/web/src/lib/routes.ts
@@ -128,7 +128,11 @@ function asWindow(segment: string | undefined): WindowName | null {
   // A link from before the rename. Resolved here rather than rejected, so an
   // address somebody shared still opens the page it named — `href` will then
   // write the block count back into the bar.
-  return (segment && LEGACY_WINDOWS[segment]) ?? null
+  //
+  // The empty segment is checked separately rather than leaning on `&&`: that
+  // form returns `''` for an empty path, which is neither a window nor null.
+  if (!segment) return null
+  return LEGACY_WINDOWS[segment] ?? null
 }
 
 /**