- add .id(selectedThread?.id) to ThreadDetailView to force SwiftUI NavigationSplitView detail re-evaluation on selection change - selectMailbox clears selectedThread/messages to avoid stale state - remove defer/project buttons from folder toolbar (4 buttons instead of 7), keyboard shortcuts still work Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>