diff --git a/packages/web-ui/src/components/MessageEditor.ts b/packages/web-ui/src/components/MessageEditor.ts
index f0987c4d..9a12f1d0 100644
--- a/packages/web-ui/src/components/MessageEditor.ts
+++ b/packages/web-ui/src/components/MessageEditor.ts
@@ -60,6 +60,9 @@ export class MessageEditor extends LitElement {
 	};
 
 	private handleKeyDown = (e: KeyboardEvent) => {
+		// Ignore key events during IME composition (e.g. CJK input)
+		if (e.isComposing || e.key === "Process") return;
+
 		if (e.key === "Enter" && !e.shiftKey) {
 			e.preventDefault();
 			if (!this.isStreaming && !this.processingFiles && (this.value.trim() || this.attachments.length > 0)) {
diff --git a/packages/web-ui/src/dialogs/ModelSelector.ts b/packages/web-ui/src/dialogs/ModelSelector.ts
index 192c3c53..8c864459 100644
--- a/packages/web-ui/src/dialogs/ModelSelector.ts
+++ b/packages/web-ui/src/dialogs/ModelSelector.ts
@@ -113,6 +113,9 @@ export class ModelSelector extends DialogBase {
 
 		// Add global keyboard handler for the dialog
 		this.addEventListener("keydown", (e: KeyboardEvent) => {
+			// Ignore key events during IME composition (e.g. CJK input)
+			if (e.isComposing || e.key === "Process") return;
+
 			// Get filtered models to know the bounds
 			const filteredModels = this.getFilteredModels();