I don't like having boxes put in everything I animate, it seems pointless.
This may be a bug or I am not doing this right.
For example I make 3 keyframes: 
I pose the right hand in the in front on frame 1 making a keyframe.
I pose the right hand giving a salute on frame 60 making a keyframe.
I pose the right hand on hip at frame 120 making a keyframe.



If I delete at frame 60 the Motion Layer's Rarm keyframe, delete the salute, the hand should slowly move from the front to the side of the avatar, it should average between frame 1 and 120 instead it does a reset T-pose. 

Can I just pose like I did with iClone 6? Is there a setting for this?

I know I'm suppose to Merge Clip (I know... bug, doesn't work) but what was wrong with iClone 6 just clipless keyframing?

It's just a guess, but I think they had to merge clips and keyframes in order for the Curve Editor to work.

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I cannot replicate that (in both modes - with and without clip auto-extend). Removing a middle key-frame results in normal average between frame 1 and 120
My guess is, it is either a bug (some phantom key-frame is created), or one or more axis for upper and lower arm rotation is getting curved to extreme for some reason.
Try resetting to linear type transition curve for the frame 120 to restore *normal* transition.

I wasn't expecting this reply. 
A phantom keyframe... hmmm. This occurs every time. The behavior is:
A keys is missing = Default reset angle AKA T-pose.
I'll test it some more and I'll post here if I get different results.