This is a minimal example condensed from an HTML-encoded e-mail found in the wild. To use:

  1. Launch screen
  2. In the screen session, load this with w3m (Lynx has its own bugs; other text browsers are untested)
  3. Move the cursor to one of the lines containing text order marks.
  4. Move the cursor right and watch as the display becomes corrupt. The text changes from 'ab cd ef g' to 'abcce g  g'.
  5. For more fun, try to copy the text into screen's copy buffer.

For other examples using mutt, see https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=655589.

You can convince yourself that this is a screen bug by repeating these steps in an xterm without screen.

Left-to-right marks: ab‎cd‎ef‎g

Right-to-left marks: ab‏cd‏ef‏g