Appearance
EL erases with bg color
EL (Erase in Line) should fill erased cells with the current background color, not the default background. When a background color is set via SGR (e.g., SGR 42 for green) before issuing EL, the erased area should be painted with that background color. This is how TUI applications create colored status bars, highlighted regions, and filled backgrounds — they set a background color and erase the line to paint the entire line with that color.
How this is testedautomated
Set green background with
Set green background with
\x1b[42m, write text, move to start of line, send \x1b[K (EL 0), verify erased cells have the green background color.The same probe runs against headless backends (via Termless) and real terminal apps (via a daemon launched in each terminal). This lets us distinguish parser correctness from rendering correctness.
Analysis2026-04-06
Supported by 12 of 14 backends (86%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | |
| Ghostty | 1.3.1 | ✓ yes | |
| VS Code | ✓ yes | ||
| Warp | ✓ yes | ||
| Cursor | ✓ yes | ||
| Terminal.app | ✓ yes |
Headless Backends
Parser correctness only — a ✓ means the parser accepts the sequence.
| Backend | Version | Support | Notes |
|---|---|---|---|
| Alacritty | 0.26.0 | ✓ yes | |
| Kitty | 0.40.0 | ✓ yes | |
| vterm | 0.2.0 | ✓ yes | |
| xterm.js | 5.5.0 | ✓ yes | |
| vt100.js | 0.2.1 | ✗ no | EL doesn't preserve SGR background — pure TypeScript emulator |
| WezTerm | 0.1.0-fork.5 | ✗ no | EL doesn't preserve SGR background in headless mode |