UNDO reliability...

Version info: Intellicad 7.1.1644.53233.P

I have often noticed UNDO does not produce the expected result.  I have a suspicion the problem might be related to the use of the ESC key to cancel commands or hit while no command is active? Here is a recent list of commands executed, I wanted to go back and change the radius used for the FILLET:

• POLYLINE
• FILLET
• EXPLODE
• ERASE
• ERASE
• TRIM
• PEDIT (join)
• PEDIT (accidentally issued - cancelled)

And now the command output copied from the command window:

Command: u
Undo: (EDITPLINE)
Command:
_U
Undo: (Unknown group)
Command:
_U
Undo: (EDITPLINE)
Command:
_U
Undo: (Unknown group)
Command:
_U
Undo: (TRIM)
Command:
_U
Undo: (ERASE)
Command:
_U
Undo: (ERASE)
Command:
_U
Undo: (EXPLODE)

The problem I have is by the time the EXPLODE was undone the polyline was gone from the drawing.

Next I tried to repeat it and this time the arc from the exploded polyline remained, could be selected and _DELETE continued to report it found one entity as I tried several time to delete it. Finally I issued a REGEN and the arc disappeared. Still the original polyline does not exist.

Okay, I have just done another test with the log file on and a script recording. I'll send them in via email to see if they are any help.

Is anyone else noticing anything odd with UNDO?