Disable Mountain Lion Dictionary Gesture

Ever since Lion I've been using Better Touch Tool in order to have the three finger tap gesture trigger a middle click. Now, in Mountain Lion, Apple has changed the in-line dictionary definition gesture from three finger double tap to three finger tap. I am finding that sometimes I get middle click and sometimes I get a dictionary definition. How can I disable Apple's dictionary definition gesture?

Edit: sometimes I am getting both a middle click and a dictionary definition.

A similar question was posted on AskDifferent.

From the accepted answer by Daniel Lawson:

In System Preferences under Trackpad then Point & Click, uncheck Look up.