How to fix mouse click and drag hang in Unity 5.2.3.p2 OSX

Just got a new Macbook Pro 13" Retina, and Unity runs super-fast, with the paralyzing irritation that while in Editor, clicking and dragging transform handles (translation, rotation, scaling) of GameObjects in-Scene drags correctly for about 0.5 seconds, then hangs for about 1 second, then “catches up” to the current mouse position with a “skip”, basically making what should be a 1 second precision transformation tune into a frustrating 6 second imprecise operation.

Have you experienced this? Have you found a fix? Please help my sanity!

OSX 10.11.2, 16GB RAM
Unity 5.2.3.p2

ANSWER:

This was too strange. Found the answer on a Mac OSX forum. Buried in the “System Preferences : Accessibility Options : Trackpad Options…” is a checkbox called “Enable Dragging”. This was unchecked as a factory default. I checked it. Problem solved. For both trackpad and mouse.