Illustrator CS4: Keystroke to initiate auto-dupliaction - how to deactivate?

[leepaulvickersdesign]

I seem to accidentally initiated an automatic duplication setting, so that anything I drag duplicates as if I've also hit the Alt key - and I can't find how to undo it! Both the Selection arrow and Direct Selection arrow do this.

A quit/restart has no effect.

Been using Illy for 8 years and I've never seen this before, but I've done it amidst frantic keyboard shortcutting!

 

[leepaulvickersdesign]

Ignore this, it seemed to be an OS thing - fixed with a restart.

 

[leepaulvickersdesign]

Hmm, this has happened again this evening. Anyone else experienced this?

CS4 on OS10.6.6 and a crappy Wacom tablet.