GNU Emacs 28.1 has broken colors when opened in a screen session with the COLORTERM environment variable set to COLORTERM=truecolor.
To reproduce: 1. Open a terminal that supports 24-bit color (e.g. GNOME Terminal) 2. Run export COLORTERM=truecolor (this is already set by default in many terminal configs) 3. Create a screen session by running screen foo 4. Launch GNU Emacs 28.1 5. Run M-x list-colors-display Expected behavior: Emacs shows the full spectrum of colors supported in the current terminal Actual behavior: Emacs shows the names of the full spectrum of colors, but almost all of them are displayed in various shades of gray. Workaround: Add unsetenv COLORTERM to ~/.screenrc The root cause is that GNU Emacs 28.1 added code that enables 24-bit color if the COLORTERM=truecolor, but screen doesn't actually pass through 24-bit color values correctly. Until screen has support for 24-bit color values, it would be nice if it automatically unset the COLORTERM environment variable during startup.
