message: Clear `top` when not sticking headers to the top
  Fixes
diff: @@ -108,6 +108,7 @@ export default class LeftPanel2 extends React.Component<IProps, IState> {
  header.classList.add("mx_RoomSublist2_headerContainer_sticky");
  header.classList.add("mx_RoomSublist2_headerContainer_stickyBottom");
  header.style.width = `${headerStickyWidth}px`;
  + header.style.top = "unset";
  gotBottom = true;
  } else if (slRect.top < top) {
  header.classList.add("mx_RoomSublist2_headerContainer_sticky");
  @@ -119,6 +120,7 @@ export default class LeftPanel2 extends React.Component<IProps, IState> {
  header.classList.remove("mx_RoomSublist2_headerContainer_stickyTop");
  header.classList.remove("mx_RoomSublist2_headerContainer_stickyBottom");
  header.style.width = `unset`;
  + header.style.top = "unset";
  }
  }
  };
  