Here are a few of the improvements either recently added or that will be added in the next few days:
– When scrolling in the preview pane, the column headings don’t scroll out of view.
– After checking the box next to a message, the message no longer becomes unchecked automatically just because you have clicked on another message.
– And this is my favorite: rolling select. If you click to check a box and, while still holding the left mouse button down, move the mouse down or up across the check boxes of other messages to check their boxes as well. This also works to uncheck boxes.