Using mouse to select text with tmux sometimes is inefficient. For my setup, I’ll have to press shift key during text selection and keyboard copy will convert empty line as spaces. The following 2 lines in the configuration file works with version 2.8 (latest at the time of writing).
Tmux is a terminal multiplexer, the main feature of it for me is to split window side by side, one for doing debugging, the other for coding. I know there are some substitutions available, such as konsole and terminator but I find tmux handy.