fix(tui): restored windows terminal appearance polling

Added the scoped OSC 11 polling fallback for native Windows Terminal when Mode 2031 appearance notifications are unsupported, preserving the no-poll behavior for other terminals.

Fixes #5091

packages/tui/CHANGELOG.md

@@ -58,6 +58,9 @@
 
 - Improved row alignment and spacing for `align`, `gather`, and `array` environments
 - Updated matrix environments to render as baseline-aligned grids with stretched brackets
+### Fixed
+
+- Fixed native Windows Terminal sessions missing mid-run light/dark theme changes when Mode 2031 appearance notifications are unavailable by polling OSC 11 only on that host path ([#5091](https://github.com/can1357/oh-my-pi/issues/5091)).
 
 ## [16.4.0] - 2026-07-10
 

packages/tui/src/terminal.ts

@@ -24,6 +24,7 @@ import { type HangulCompatibilityJamoWidth, setHangulCompatibilityJamoWidth } fr
 const TERMINAL_PROGRESS_KEEPALIVE_MS = 1000;
 const TERMINAL_PROGRESS_ACTIVE_SEQUENCE = "\x1b]9;4;3\x07";
 const TERMINAL_PROGRESS_CLEAR_SEQUENCE = "\x1b]9;4;0;\x07";
+const WINDOWS_TERMINAL_OSC11_POLL_MS = 30_000;
 // Hangul Compatibility Jamo (U+3131..=U+318E) render width is terminal-dependent:
 // Ghostty follows UAX#11 (2 cells); Terminal.app and iTerm2 render narrow (1),
 // matching the macOS platform default. Override only for terminals known to
@@ -48,6 +49,11 @@ function shouldEnableModifyOtherKeysFallback(env: NodeJS.ProcessEnv = Bun.env):
 	return TERMINAL.id !== "base" && TERMINAL.id !== "trueColor";
 }
 
+function shouldPollWindowsTerminalAppearance(env: NodeJS.ProcessEnv = Bun.env): boolean {
+	if (process.platform !== "win32") return false;
+	if (!env.WT_SESSION) return false;
+	return !env.TERM_PROGRAM || env.TERM_PROGRAM.toLowerCase() === "windows_terminal";
+}
 /**
  * Maximum encoded UTF-8 bytes per `process.stdout.write` call on Windows.
  *
@@ -499,6 +505,7 @@ export class ProcessTerminal implements Terminal {
 	#reportedColumns?: number;
 	#reportedRows?: number;
 	#mode2031DebounceTimer?: Timer;
+	#windowsTerminalAppearancePollTimer?: Timer;
 	#progressTimer?: Timer;
 
 	get kittyProtocolActive(): boolean {
@@ -627,7 +634,8 @@ export class ProcessTerminal implements Terminal {
 		// WezTerm) detect the appearance once at startup and pick up later OS
 		// theme changes on next launch. Earlier builds polled OSC 11 every 30 s
 		// here for those terminals, but each poll's OSC 11/DA1 write wiped the
-		// user's active text selection on several of them (#3297).
+		// user's active text selection on several of them (#3297). Native Windows
+		// Terminal gets a scoped fallback after DECRQM confirms 2031 is unsupported.
 
 		// Probe DEC private-mode support via DECRQM. 2026 (synchronized output)
 		// gates the renderer's begin/end markers; 2048 (in-band resize) is enabled
@@ -1167,8 +1175,25 @@ export class ProcessTerminal implements Terminal {
 			}
 		}
 		if (mode === 2048 && supported) this.#enableInBandResize();
+		if (mode === 2031) this.#syncWindowsTerminalAppearancePolling(supported);
 	}
 
+	#syncWindowsTerminalAppearancePolling(mode2031Supported: boolean): void {
+		if (mode2031Supported || !shouldPollWindowsTerminalAppearance() || this.#dead) {
+			this.#clearWindowsTerminalAppearancePoll();
+			return;
+		}
+		if (this.#windowsTerminalAppearancePollTimer) return;
+		this.#windowsTerminalAppearancePollTimer = setInterval(() => {
+			this.#queryBackgroundColor();
+		}, WINDOWS_TERMINAL_OSC11_POLL_MS);
+	}
+
+	#clearWindowsTerminalAppearancePoll(): void {
+		if (!this.#windowsTerminalAppearancePollTimer) return;
+		clearInterval(this.#windowsTerminalAppearancePollTimer);
+		this.#windowsTerminalAppearancePollTimer = undefined;
+	}
 	#disableXtermScrollToBottomMode(mode: number): void {
 		if (this.#xtermScrollToBottomRestoreModes.has(mode) || this.#dead) return;
 		this.#xtermScrollToBottomRestoreModes.add(mode);
@@ -1326,6 +1351,7 @@ export class ProcessTerminal implements Terminal {
 		}
 		this.#appearanceCallbacks = [];
 		this.#osc11Pending = false;
+		this.#clearWindowsTerminalAppearancePoll();
 		this.#osc11QueryQueued = false;
 		this.#osc11ResponseBuffer = "";
 		this.#osc99PendingId = undefined;

packages/tui/test/terminal-appearance.test.ts

@@ -17,6 +17,8 @@ const stdoutRowsDescriptor = Object.getOwnPropertyDescriptor(process.stdout, "ro
 const stdinSetRawModeDescriptor = Object.getOwnPropertyDescriptor(process.stdin, "setRawMode");
 const originalWslDistroName = Bun.env.WSL_DISTRO_NAME;
 const originalWslInterop = Bun.env.WSL_INTEROP;
+const originalWtSession = Bun.env.WT_SESSION;
+const originalTermProgram = Bun.env.TERM_PROGRAM;
 
 // These suites drive the real ProcessTerminal start()/probe pipeline, so they
 // opt out of the test-default headless suppression and restore it per case.
@@ -56,6 +58,8 @@ describe("ProcessTerminal OSC 11 appearance detection", () => {
 		restoreProperty(process, "platform", processPlatformDescriptor);
 		restoreEnv("WSL_INTEROP", originalWslInterop);
 		restoreEnv("WSL_DISTRO_NAME", originalWslDistroName);
+		restoreEnv("WT_SESSION", originalWtSession);
+		restoreEnv("TERM_PROGRAM", originalTermProgram);
 	});
 
 	function setupTerminal() {
@@ -232,6 +236,29 @@ describe("ProcessTerminal OSC 11 appearance detection", () => {
 		terminal.stop();
 	});
 
+	it("periodically re-queries OSC 11 under native Windows Terminal when Mode 2031 is unavailable (#5091)", () => {
+		vi.useFakeTimers();
+		Object.defineProperty(process, "platform", { value: "win32", configurable: true });
+		Bun.env.WT_SESSION = "test-wt-session";
+		Bun.env.TERM_PROGRAM = "Windows_Terminal";
+		const { terminal, queryCount } = setupTerminal();
+
+		process.stdin.emit("data", "\x1b]11;rgb:0000/0000/0000\x07");
+		process.stdin.emit("data", "\x1b[?2031;0$y");
+		// Drain startup sentinels in send order: keyboard, OSC 11, DEC 2026,
+		// DEC 2048, DEC 2031, and xterm ?1010/?1011.
+		for (let i = 0; i < 7; i++) {
+			process.stdin.emit("data", "\x1b[?1;2c");
+		}
+		const afterStartup = queryCount();
+
+		vi.advanceTimersByTime(30_000);
+
+		expect(queryCount()).toBe(afterStartup + 1);
+
+		terminal.stop();
+	});
+
 	it("does not periodically re-query OSC 11 under WSL either (#3297)", () => {
 		vi.useFakeTimers();
 		Object.defineProperty(process, "platform", { value: "linux", configurable: true });