iTerm2 (a popular open source terminal emulator for Mac) supports this automatically for all TUI programs, by recognising the box characters. You select multi-

iTerm2 (a popular open source terminal emulator for Mac) supports this automatically for all TUI programs, by recognising the box characters. You select multi-line text inside the box and it behaves as if the box is a mini terminal. I don't know which other terminal emulators have the same feature.