I love the new session management in the latest versions, but there a couple UI feature that would be great to have more user-friendly, especially in regards to keyboard interaction.
1. The Login dropdown dialog should be focusable with the keyboard. I suggest using Alt+L to focus, then the user can easily press down arrow to expand it, and for instance press 'p' to open in Putty. Or just have it expand as standard on Alt+L.
Default focus is just 'Login' and user can just press Enter to do a login.
2. Same with the Save dialog in Edit Session, it should focus on Alt+S (not just save as it does now), since users should be able to do "Save As" without resorting to the mouse or pressing Tab a lot.
Maybe the dialogs should expand on pressing the keyboard shortcut, so it's easier to see the other alternatives.
There are just suggestions for a more User-friendly UI - Winscp generally is otherwise a great example of good UI design, compared to other tools of the same type :)