My workaround to quickly find notes that are in local folders:
View all notes in list view. Unsynced notes in synchronized notebooks will show a dot in the SyncStatus column. Unfortunately notes in local notebooks (never synced) do not show a dot or any indication that they do not sync. As a workaround you can sort by SyncStatus and float local notes to the top. Edit a test note from a known synchronized notebook. Sync with the server. Click on the sync status header to toggle the sort order. Look for notes listed above your test note. Click the sync status header again to flip the sort. I