Postbox 2 includes a bunch of keyboard shortcuts to make it easier to navigate through the interface and quickly triage messages:
We've simplified the tab functions within the three pane interface, and have made it much more obvious as to what is currently being selected.
You can now use the left and right arrow keys to move between the various panes in the main window:
When a message is selected, you can use the right arrow to open that message in a new tab, and the left arrow will move to the pane to the left.
When a conversation is selected, the right arrow will expand the conversation, and the left arrow will collapse it and then move to the pane to the left.
Some of the new short cuts in Postbox 2 include access to Quick Folder Switch, Quick Move, Quick Reply, and the ability to open and close the Inspector Pane, Folder Pane, and Focus Panes to customize your view.