Fixed! The issue was in the [useEffect](file:///private/var/folders/kr/jdxkcn7129j376nrg0stj9zm0000gn/T/vibe-kanban/vk-db4e-the-close/frontend/src/pages/project-tasks.tsx#L91-L106) that handles URL changes. It only opened the panel when a taskId was present but didn't close it when the taskId was removed from the URL. (#203)

The fix adds an `else` condition that closes the panel (`setIsPanelOpen(false)`) and clears the selected task (`setSelectedTask(null)`) when there's no `taskId` in the URL.

frontend/src/pages/project-tasks.tsx

@@ -98,6 +98,10 @@ export function ProjectTasks() {
         });
         setIsPanelOpen(true);
       }
+    } else {
+      // Close panel when no taskId in URL
+      setIsPanelOpen(false);
+      setSelectedTask(null);
     }
   }, [taskId, tasks]);