message: Move history with alt up/down regardless of where selection is
diff: @@ -1130,17 +1130,6 @@ export default class MessageComposerInput extends React.Component {
  onVerticalArrow = (e, up) => {
  if (e.ctrlKey || e.shiftKey || e.metaKey) return;
  - // selection must be collapsed
  - const selection = this.state.editorState.selection;
  - if (!selection.isCollapsed) return;
  - // and we must be at the edge of the document (up=start, down=end)
  - const document = this.state.editorState.document;
  - if (up) {
  - if (!selection.anchor.isAtStartOfNode(document)) return;
  - } else {
  - if (!selection.anchor.isAtEndOfNode(document)) return;
  - }
  -
  const shouldSelectHistory = e.altKey;
  const shouldEditLastMessage = !e.altKey && up && !RoomViewStore.getQuotingEvent();
  @@ -1152,6 +1141,17 @@ export default class MessageComposerInput extends React.Component {
  e.preventDefault();
  }
  } else if (shouldEditLastMessage) {
  + // selection must be collapsed
  + const selection = this.state.editorState.selection;
  + if (!selection.isCollapsed) return;
  + // and we must be at the edge of the document (up=start, down=end)
  + const document = this.state.editorState.document;
  + if (up) {
  + if (!selection.anchor.isAtStartOfNode(document)) return;
  + } else {
  + if (!selection.anchor.isAtEndOfNode(document)) return;
  + }
  +
  const editEvent = findEditableEvent(this.props.room, false);
  if (editEvent) {
  // We're selecting history, so prevent the key event from doing anything else
  