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Shift+Enter intercepted, not forwarded to PTY (breaks Kitty keyboard protocol) #2970
Description
Shift+Enter is intercepted and not forwarded to the PTY
Summary
Superset's terminal intercepts Shift+Enter via attachCustomKeyEventHandler and prevents it from reaching the PTY. This breaks terminal applications that rely on the Kitty keyboard protocol to distinguish Shift+Enter from plain Enter — notably pi, Claude Code, and other CLI tools that use Shift+Enter for multi-line input.
Expected behavior
When a terminal application has enabled the Kitty keyboard protocol (via CSI > 1 u), Shift+Enter should be forwarded to the PTY as the CSI u sequence \x1b[13;2u, allowing the application to distinguish it from plain Enter.
Actual behavior
Shift+Enter is unconditionally swallowed by Superset's custom key event handler:
// helpers.ts ~line 536
const isShiftEnter =
event.key === "Enter" &&
event.shiftKey &&
!event.metaKey &&
!event.ctrlKey &&
!event.altKey;
if (isShiftEnter) {
if (event.type === "keydown" && options.onShiftEnter) {
event.preventDefault();
options.onShiftEnter();
}
return false; // ← prevents xterm.js from sending anything to the PTY
}The return false prevents xterm.js from processing the key, so the Kitty protocol response is never generated regardless of whether the application requested it.
Affected applications
- pi — uses Shift+Enter for new line in its TUI editor
- Claude Code — uses Shift+Enter for multi-line input
- Any terminal application using the Kitty keyboard protocol
Suggested fix
Check whether the Kitty keyboard protocol is active before intercepting. xterm.js tracks this internally. When the protocol is enabled, Shift+Enter should pass through to the PTY so xterm.js can encode it as \x1b[13;2u.
A simpler alternative: add a per-terminal or global setting to disable the Shift+Enter interception, e.g.:
{
"terminal.shiftEnterBehavior": "passthrough" | "superset"
}Workaround
Users can rebind the new-line action in pi to Ctrl+J via ~/.pi/agent/keybindings.json:
{
"tui.input.newLine": ["shift+enter", "ctrl+j"]
}Environment
- Superset: latest
- macOS
- pi / Claude Code running inside Superset terminal
Activity
fix: solve #2970 — pass Shift+Enter through to PTY when Kitty keyboar…
sarthaksrinivas commentedon Apr 6, 2026
I run pi inside Superset as my daily driver.
Shift+Enteris the default keybinding for inserting a new line in your TUI editor (tui.input.newLine), and since Superset intercepts it before it reaches the PTY, multi-line input is completely broken (every Shift+Enter submits the message instead).I have confirmed that pi requests the Kitty keyboard protocol on startup via
CSI > 1 u, so the approach in #2971 (checkingkittyKeyboard.flagsbefore intercepting) would fix this for my workflow.Would love to see #2971 merged — happy to test a build if that would help move it forward.
sarthaksrinivas commentedon Apr 8, 2026
#3251
@marvtub does this solve your issue?
Kitenite commentedon May 6, 2026
Related reports (cross-referenced during issue triage — same area, may or may not share a root cause):
Kitenite commentedon Jul 11, 2026
Closing as a duplicate of #5604, the consolidated tracker for stale
terminal-inputissues from the July 2026 stale-issue sweep (no activity since 2026-06-01). If this still applies on a current build, comment on #5604 and we'll reopen.