Due to its use of tables, when you do a copy from Patch Viewer, the copied lines are essentially meaningless. There is no way to even copy a single section of a single patch without getting both the old and new sides in the copy.

It might be possible to do this by having the left and right sides of a section each be a single table cell, and insert blank lines or maybe tricky CSS empty lines (divs with a particular height) to make everything line up. It's still less meaningful because you get incorrect blank lines. The problem with the current implementation is that every line is a cell.