message: Don't send mouse events for stuff which happens in the scrollback area
diff: @@ -1029,6 +1029,10 @@ export class TerminalViewer extends ViewerElement implements SupportsClipboardPa
  if (pos === null) {
  return;
  }
  + if (pos.row - this._terminalFirstRow < 0) {
  + // Don't send mouse events for stuff which happens in the scrollback area.
  + return;
  + }
  // FIXME use the 'buttons' API.
  const button = ev.button !== undefined ? ev.button : (ev.which !== undefined ? ev.which - 1 : null);
  