Yeah, I considered both of those. The tabs in custom windows would make column selection useful, though that's mostly limited to custom windows rather than channel/query. As far as code, that also came to mind. The reason I didn't really think it was more than a minor convenience is because you are limited by line wrapping, which can happen often in scripts. Now, if it were possible to disable line wrapping AND have column highlighting, then I can see a real benefit to it. Otherwise, you gain a slight benefit in that you can copy some pasted scripts, but not others.
Anyhow, I just wanted to see what the reasons behind the original post were. It helps to show why it's wanted and what benefit there is so Khaled can decide if the benefits are worth it. Of course, I don't think adding column highlighting is a major undertaking.
The only real problem that it would have to solve is control codes. If you're on line 2 of a wrapped text and are not copying the end of the line before or the beginning of line 2, the highlighting would have to figure out what color or bold/underline/etc is needed on line 2.