Appearance
CUU stops at top
CUU (Cursor Up, CSI Pn A) should stop at the top margin of the scroll region, or row 1 if no scroll region is set. Moving up with a count exceeding the current row should clamp to row 0 rather than wrapping to the bottom. This prevents cursor escape from the visible area and is relied upon by screen-clearing routines that use large CUU counts.
How this is tested: Position at row 3, send
\x1b[999A (CUU with count 999), verify cursor stopped at row 0.Analysis2026-03-26
Supported by all 5 tested terminals — universal adoption. Part of the Core TUI baseline.
Supported by 11 of 11 backends (100%)
Terminal Applications
| Terminal | Version | Support | Notes |
|---|---|---|---|
| iTerm2 | 3.6.9 | ✓ yes | |
| Ghostty | 1.3.1 | ✓ yes | |
| VS Code | 1.112.0 | ✓ yes | |
| Warp | 0.2026.03.18.08.24.03 | ✓ yes | |
| Cursor | 2.6.21 | ✓ yes | |
| Kitty | 0.46.2 | ✓ yes | |
| Terminal.app | 2.15 | ✓ yes |