message: flex-basis to 0 so sublists shrink/grow not-relative to their content
diff: @@ -39,7 +39,15 @@ limitations under the License.
  }
  .mx_RoomSubList.resized-sized {
  - flex: 0 1 auto;
  + /*
  + flex-basis to 0 so sublists
  + are not shrinking/growing relative
  + to their content (as would be the case with auto),
  + as this intervenes with sizing an item exactly
  + when not available space is available
  + in the flex container
  + */
  + flex: 1 1 0;
  }
  .mx_RoomSubList_nonEmpty {
  