Sony HDS-7100 User Manual page 198

Undelete function
Undo function
Until you delete another keyframe, you can always recover the last
deleted keyframe, which is saved in an undelete buffer. You can
reinsert this keyframe at any position, using the following
procedure.
1
Stop the effect on the required edit point.
Regardless of the position from which the keyframe was
deleted, you can reinsert it at any position. When the edit
point is on a keyframe, the following procedure inserts the
previously deleted keyframe immediately before the edit point.
2
Press the KF EDIT ENABL button, turning it on.
3
Hold down the SHIFT button and press the UNDEL/UNDO
button.
This reinserts the keyframe from the undelete buffer.
To undo the effect of the last operation, and return to the state
before the edit, press the UNDEL/UNDO button.
This applies to operations with the BEFR/INSRT, DEL, MOD,
and KF/DUR EFF buttons.
Chapter 7 Keyframe Effects
7-15