Add multi segment drag and drop (#7536)

* drag selected segments as well as the dragged segment

* add comment

* add changelog

CHANGELOG.unreleased.md

@@ -18,6 +18,7 @@ For upgrade instructions, please check the [migration guide](MIGRATIONS.released
 - Added thumbnails to the dashboard dataset list. [#7479](https://github.com/scalableminds/webknossos/pull/7479)
 - Adhoc mesh rendering is now available for ND datasets.[#7394](https://github.com/scalableminds/webknossos/pull/7394)
 - When setting up WEBKNOSSOS from the git repository for development, the organization directory for storing datasets is now automatically created on startup. [#7517](https://github.com/scalableminds/webknossos/pull/7517)
+- Multiple segments can be dragged and dropped in the segments tab. [#7536](https://github.com/scalableminds/webknossos/pull/7536)
 
 
 ### Changed

frontend/javascripts/oxalis/view/right-border-tabs/segments_tab/segments_view.tsx

@@ -1836,9 +1836,11 @@ class SegmentsView extends React.Component<Props, State> {
         : dropTargetGroupId;
     }
     if (dragNode.type === "segment") {
-      // A segment is being dropped onto/next to a segment or group.
+      // Segment(s) were dragged onto/next to a segment or group.
+      // It is possible to drag a segment that was not selected. In that case, the selected segments are moved as well.
+      const selectedSegmentIds = this.state.selectedIds.segments;
       this.props.updateSegments(
-        [dragNode.id],
+        [dragNode.id, ...selectedSegmentIds],
         { groupId: targetGroupId },
         this.props.visibleSegmentationLayer.name,
         true,