message: debugging move markers
diff: @@ -388,7 +388,7 @@ const commands: ICmd[] = [
  export function moveMarker(flowView: FlowView, toPos: number, marker: MergeTree.Marker) {
  const curPos = getOffset(flowView, marker);
  - console.log(`move marker from ${curPos} to ${toPos}`);
  + console.log(`move marker from ${curPos} to ${toPos} ${marker.removedSeq}`);
  flowView.sharedString.cut("inclusion", curPos, curPos + marker.cachedLength);
  flowView.sharedString.paste("inclusion", toPos);
  }
  @@ -3741,7 +3741,7 @@ export class FlowView extends ui.Component {
  };
  this.element.onmouseup = (e) => {
  - this.element.onmousemove = undefined;
  + this.element.onmousemove = preventD;
  if (e.button === 0) {
  freshDown = false;
  const span = e.target as ISegSpan;
  