Update src/browser/CoreBrowserTerminal.ts

Author: Tyriar

src/browser/CoreBrowserTerminal.ts

@@ -415,9 +415,11 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
     this._register(addDisposableListener(this.textarea!, 'keydown', (ev: KeyboardEvent) => this._keyDown(ev), true));
     this._register(addDisposableListener(this.textarea!, 'keypress', (ev: KeyboardEvent) => this._keyPress(ev), true));
     this._register(addDisposableListener(this.textarea!, 'compositionstart', () => {
-      // Ensure the textarea is synced to the latest cursor location before composition begins.
-      // Some prompt UIs briefly draw helper text and then restore the cursor without triggering a
-      // new key event, which can leave IME anchoring stale until the first render tick.
+      // Ensure the textarea is synced to the latest cursor location before composition begins. This
+      // is to workaround a problem where highly dynamic TUIs like agentic CLIs reprint agressively
+      // would cause the IME to appear in the wrong position. The theory is that when the IME is
+      // triggered during a partial render the textarea position becomes locked and will not move
+      // until it is hidden and a custom move occurs.
       this._syncTextArea();
       this._compositionHelper!.compositionstart();
       this._compositionHelper!.updateCompositionElements();