In this video, I show Crossfader Overlap and A and B controls in MIDI Designer.
Crossfader Overlap lets you make a crossfader with 2 (or more) controls in MIDI Designer. A/B Values let you copy values from one set of controls (and A set) to a second set of a controls (their "B" controls). This is useful for starting your B (or A) channel with the same values at any point in time.
This video also shows crossfader overlap.
MIDI Designer: Design your perfect MIDI controller for iPad, iPhone and iPod touch.
http://MIDIdesigner.com