mrdoob/three.js — pull request #5144 by dmtaub (2014-07-29 20:26:03+00:00)
Title: Added event for start gizmo drag

Provides an event in TransformControls for when a gizmo is selected. This is necessary to cleanly prioritize selection of a gizmo over other models in the scene--for example when the gizmo is behind another model that would be selected by raycasting. The other solution would require including gizmo faces in the raycast objects array.