One of the coolest things you can do with the Notes client is plug in functionality that someone else has written. If you are like me then your mail archive has way more documents than your mail database. And going from database to database is a pain.
To help fix this, Bob Balfe wrote a plugin that can search multiple databases for you. All you need to do is drag and drop the widget from the following page:
After that it's just about clicking the databases you want to search and then running a search from the toolbar. The most amazing thing about all this is how few people know that it is available to them.