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Scrollback accumulates

Category: scrollback · Baseline: core · Tags: Xterm Extensions · Specification ↗

Tests whether lines scrolled off the top of the visible screen are preserved in the scrollback buffer. This is fundamental terminal behavior — without scrollback accumulation, users cannot scroll up to see previous output. Virtually all modern terminals maintain a scrollback buffer, though the maximum size varies.
How this is testedautomated
Write 30 lines (exceeding the 24-row screen), verify total line count exceeds 24.

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 all 12 tested terminals — universal adoption. Part of the Core TUI baseline.

Supported by 14 of 14 backends (100%)

Terminal Applications

TerminalVersionSupportNotes
iTerm23.6.9✓ yes
Ghostty1.3.1✓ yes
VS Code✓ yes
Warp✓ yes
Cursor✓ yes
Terminal.app✓ yes

Headless Backends

Parser correctness only — a means the parser accepts the sequence.

BackendVersionSupportNotes
Alacritty0.26.0✓ yes
Kitty0.40.0✓ yes
vt100.js0.2.1✓ yes
vterm0.2.0✓ yes
WezTerm0.1.0-fork.5✓ yes
xterm.js5.5.0✓ yes