Cannot select multiple lines with SideBySide renderer

[BlackbitDevs]

With SideBySide renderer the code is rendered as HTML table. When you want to select multiple lines of code on one side, automatically the code (and the line numbers) from the other side get selected as well:

This makes it impossible to copy-paste parts of the code.

[jfcherng]

I am no CSS/HTML guru. I am not going to address this personally but a pull request is welcomed.