A big and very welcome update to MarsEdit today with 5.2, including:

The “Search” field in the main window now features a filter selection to toggle between searching everything or searching just the current selection. …

A new menu item for duplicating posts …

Alt Text field in Upload Utility and Media Manager now grows vertically to accommodate longer descriptions

At last I can narrow my search to just one blog.
At last I can narrow my search to just one blog.