The suite-wide search function has had a revamp, with a number of useful features added:
optional restriction to target scope;
optional dynamic updating of existing search results as new requests are made;
ability to search selected hosts/branches within the site map, via the site map context menu.
Here's an example of using a regex search term with dynamic updating, to monitor all responses containing HTML comments as they are received from the server:
The searchable text viewer/editor used throughout Burp also now supports regex and case sensitive searches. These features are accessed via a new pop-up panel at the left of the search bar:
When you are viewing items found in a suite-wide search, the relevant options which you used in that search are automatically copied to the text viewer, so that the correct items are highlighted.