diff --git a/packages/tui/README.md b/packages/tui/README.md
index 5ae89f3d..ef02d244 100644
--- a/packages/tui/README.md
+++ b/packages/tui/README.md
@@ -115,7 +115,7 @@ editor.setAutocompleteProvider(provider);
 
 **Key Bindings:**
 - `Enter` - Submit
-- `Shift+Enter` or `Ctrl+Enter` - New line
+- `Shift+Enter`, `Ctrl+Enter`, or `Alt+Enter` - New line (terminal-dependent, Alt+Enter most reliable)
 - `Tab` - Autocomplete
 - `Ctrl+K` - Delete line
 - `Ctrl+A` / `Ctrl+E` - Line start/end
diff --git a/packages/tui/src/components/editor.ts b/packages/tui/src/components/editor.ts
index f9457649..4374775d 100644
--- a/packages/tui/src/components/editor.ts
+++ b/packages/tui/src/components/editor.ts
@@ -333,8 +333,8 @@ export class Editor implements Component {
 			// Left
 			this.moveCursor(0, -1);
 		}
-		// Regular characters (printable ASCII)
-		else if (data.charCodeAt(0) >= 32 && data.charCodeAt(0) <= 126) {
+		// Regular characters (printable characters and unicode, but not control characters)
+		else if (data.charCodeAt(0) >= 32) {
 			this.insertCharacter(data);
 		}
 	}
@@ -472,7 +472,7 @@ export class Editor implements Component {
 		// Filter out non-printable characters except newlines
 		const filteredText = tabExpandedText
 			.split("")
-			.filter((char) => char === "\n" || (char >= " " && char <= "~"))
+			.filter((char) => char === "\n" || char.charCodeAt(0) >= 32)
 			.join("");
 
 		// Split into lines
diff --git a/packages/tui/test/editor.test.ts b/packages/tui/test/editor.test.ts
new file mode 100644
index 00000000..ab9b3af2
--- /dev/null
+++ b/packages/tui/test/editor.test.ts
@@ -0,0 +1,131 @@
+import assert from "node:assert";
+import { describe, it } from "node:test";
+import { Editor } from "../src/components/editor.js";
+
+describe("Editor component", () => {
+	describe("Unicode text editing behavior", () => {
+		it("inserts mixed ASCII, umlauts, and emojis as literal text", () => {
+			const editor = new Editor();
+
+			editor.handleInput("H");
+			editor.handleInput("e");
+			editor.handleInput("l");
+			editor.handleInput("l");
+			editor.handleInput("o");
+			editor.handleInput(" ");
+			editor.handleInput("ä");
+			editor.handleInput("ö");
+			editor.handleInput("ü");
+			editor.handleInput(" ");
+			editor.handleInput("😀");
+
+			const text = editor.getText();
+			assert.strictEqual(text, "Hello äöü 😀");
+		});
+
+		it("deletes single-code-unit unicode characters (umlauts) with Backspace", () => {
+			const editor = new Editor();
+
+			editor.handleInput("ä");
+			editor.handleInput("ö");
+			editor.handleInput("ü");
+
+			// Delete the last character (ü)
+			editor.handleInput("\x7f"); // Backspace
+
+			const text = editor.getText();
+			assert.strictEqual(text, "äö");
+		});
+
+		it("deletes multi-code-unit emojis with repeated Backspace", () => {
+			const editor = new Editor();
+
+			editor.handleInput("😀");
+			editor.handleInput("👍");
+
+			// Delete the last emoji (👍) - requires 2 backspaces since emojis are 2 code units
+			editor.handleInput("\x7f"); // Backspace
+			editor.handleInput("\x7f"); // Backspace
+
+			const text = editor.getText();
+			assert.strictEqual(text, "😀");
+		});
+
+		it("inserts characters at the correct position after cursor movement over umlauts", () => {
+			const editor = new Editor();
+
+			editor.handleInput("ä");
+			editor.handleInput("ö");
+			editor.handleInput("ü");
+
+			// Move cursor left twice
+			editor.handleInput("\x1b[D"); // Left arrow
+			editor.handleInput("\x1b[D"); // Left arrow
+
+			// Insert 'x' in the middle
+			editor.handleInput("x");
+
+			const text = editor.getText();
+			assert.strictEqual(text, "äxöü");
+		});
+
+		it("moves cursor in code units across multi-code-unit emojis before insertion", () => {
+			const editor = new Editor();
+
+			editor.handleInput("😀");
+			editor.handleInput("👍");
+			editor.handleInput("🎉");
+
+			// Move cursor left over last emoji (🎉)
+			editor.handleInput("\x1b[D"); // Left arrow
+			editor.handleInput("\x1b[D"); // Left arrow
+
+			// Move cursor left over second emoji (👍)
+			editor.handleInput("\x1b[D");
+			editor.handleInput("\x1b[D");
+
+			// Insert 'x' between first and second emoji
+			editor.handleInput("x");
+
+			const text = editor.getText();
+			assert.strictEqual(text, "😀x👍🎉");
+		});
+
+		it("preserves umlauts across line breaks", () => {
+			const editor = new Editor();
+
+			editor.handleInput("ä");
+			editor.handleInput("ö");
+			editor.handleInput("ü");
+			editor.handleInput("\n"); // new line
+			editor.handleInput("Ä");
+			editor.handleInput("Ö");
+			editor.handleInput("Ü");
+
+			const text = editor.getText();
+			assert.strictEqual(text, "äöü\nÄÖÜ");
+		});
+
+		it("replaces the entire document with unicode text via setText (paste simulation)", () => {
+			const editor = new Editor();
+
+			// Simulate bracketed paste / programmatic replacement
+			editor.setText("Hällö Wörld! 😀 äöüÄÖÜß");
+
+			const text = editor.getText();
+			assert.strictEqual(text, "Hällö Wörld! 😀 äöüÄÖÜß");
+		});
+
+		it("moves cursor to document start on Ctrl+A and inserts at the beginning", () => {
+			const editor = new Editor();
+
+			editor.handleInput("a");
+			editor.handleInput("b");
+			editor.handleInput("\x01"); // Ctrl+A (move to start)
+			editor.handleInput("x"); // Insert at start
+
+			const text = editor.getText();
+			assert.strictEqual(text, "xab");
+		});
+	});
+});