No, I had no cut off either, at all. I've been using this for one more day and I renew my total appreciation for the way it works. Fantastic!

Now, as to the slider bar, I was thinking of something like what papinst showed you, but I admit it is a quite controversial way to look at it. What papinst said makes perfectly sense, as long as you are sitting in the middle of the car, or better of the speakers. Now, this whole thing is needed just because you are NOT sitting in the middle of the car. So, I had this idea, which maybe you like.
Assuming you are sitting in the left seat, you'll hear the "center" of the stereo image shifted to the extreme LEFT, since you are closer to the left speaker. So, when NO ADJUSTMENT has been done, the slider bar should look simply like this (just the bar, no slider, and with the two labels Left Seat and Right Seat, as shown.The reason for this is that the slider overlaps with the exremes themselves. See below why):

L. Seat - R. Seat
||----------|----------||

all bright or all dimmed

Ideally, the two extremes of the bar represent the location of the speakers (let's say the doors of your car). The two half of the bar represent the stereo image as perceived from the two front seats. i.e the left half represents the point of "view" of the person sitting on the left seat, and the right half represents the point of view of the person sitting on the right seat, respectively.

Now, when I delay the LEFT channel, I do so just to move the stereo image further from the speaker I am closer to, in this example the LEFT one. So, supposing I delayed the LEFT speaker a little bit, I would have this

L. Seat - R. Seat
||--+-------|----------||

bright - dimmed

If I decided to delay still the LEFT channel some more, I would have this:

L. Seat - R. Seat
||-------+--|----------||

bright - dimmed

(Notice, I imagine the slider never crossing the middle of the bar if not when sitching to the OTHER (RIGHT) channel delay. See below what I mean*.)



If instead I decided to delay the RIGHT channel, I would see something like:

L. Seat - R. Seat
||----------|-------+--||

dimmed - bright

And if I delayed the RIGHT channel more, I would have

L. Seat - R. Seat
||----------|--+-------||

dimmed - bright

*Also, I noticed that if you keep turning the knob, you move from the LEFT maximum delay to RIGHT maximum delay. This is perfectly meaningful in this graphic UI, since it would consist, graphically, in shifting

from ||--------+-|----------|| to ||----------|-+--------|| , i.e. from the situation in which the person sitting on the left seat perceives the center of the stereo image at his right, to the situation in which the person sitting on the right seat perceives the stereo image on his left.

I hope I was at elast a little bit clear...

What do you think?