I support the suggestion. Column selection is a great feature in various environments (not just text/code editors), including mirc: more often than I can remember, I have needed to copy a bunch of lines from one person (eg somebody pasting code) without including the "[HH:nn] <nick>" part. Similarly, since mirc supports tabbed text in custom windows (/window -t), column selection is a natural feature to have (what if I want to copy an entire column from that window).
