I am very happy to see the box-editing feature (text changes applies to every line selected by the user) in the latest alpha version, but I think the functionality is not good enough. It's better for the editor to stay in box-editing mode unless user press up or down cursor or escape key; that means backspace should delete one character, not all the whole changes made since box-editing began and ctrl-z should not cancel box-editing mode. The power column mode in Boxer text editor is really good (I think it's better than ultraedit) and maybe you can take it as an example.