Widgit Rotate Tool

This tool lets you modify a curve in a controlled manner.

When you are editing a curve you can use LMB+Crtl to choose the widgit rotate tool.

Using Widgit Rotate

Select a curve by dragging with the RMB. It will turn yellow when selected.
Select the widgit rotate tool from the Tools Panel, or press "D" to select the Curve Drawing tool type, then hold Ctrl to access the widgit rotate tool. The cursor should change to this: Now hold the LMB down on part of the curve. You will notice the curve turns yellow under the cursor, and turns to red further from the cursor. I have exaggerated this in the image!
Drag mouse around, keeping the button held down. You will see the curve rotate about the point you started draging at. Try dragging a different part of the curve. The the yellow parts of the curve twist around, the red parts remain close to their original positions.

Widgit Rotate Controls

You can adjust the shape and area of effect of the widgit tool on the Widgit Rotate Panel. Try dragging on the shape and scale controls to change the area and falloff of the effect. The widgit rotate tool defaults to a much smaller scale than the widgit move tool, this is to help you tidy up the ends of objects to get them matching smartly.