I recently tried scrolling the columns in a big CSV but couldn't.
I found out that the problem was that the last line had fewer columns.
It surprised me at the time, so I thought I should mention it here.
Feel free to close it if you think this is too non-standard and doesn't have to be supported.

Here's an example file. In a 216 column terminal, whatever I do, I can't make csvlens display the last columns.
foo.csv