message: Fix bug where the context menu didn't appear on terminal viewers surrounded by frames.
diff: @@ -1152,15 +1152,14 @@ export class TerminalViewer extends ViewerElement implements SupportsClipboardPa
  ev.stopPropagation();
  }
  - if (this._emulator === null) {
  - return;
  - }
  + if (this._emulator != null) {
  if ( ! this.hasFocus()) {
  this.focus();
  }
  if (this._handleEmulatorMouseEvent(ev, this._emulator.mouseDown.bind(this._emulator))) {
  return;
  }
  + }
  if (isRightMouseButton) {
  this._handleContextMenu(ev);
  