From Synfig Studio :: Documentation
The "Rotate Tool" rotate the selected Handles. It works much like to Transform Tool except for when multiple Handles are selected.
- Allow Scale : Allow the selected Handles to be scaled and rotated at the same time.
Select multiple Handles, by either:
- Pressing ControlA to select all Handles
- Dragging a rectangle around a group of Handles
- Holding the Control key while clicking Handles to toggle their selected status
Then drag one of the selected Handles. All the selected Handles will move, rotating about the center of the selected handles group.