Some tools not working in Illustrator when using puppet file

This is more of an annoyance than anything.  I build my characters onto the Illustrator file that came with one of the premade character puppets, using it as a kind of a template with the mouth visemes, etc., already in place.

For some reason, once I started doing this, the knife and lasso tools (possibly others) don't work on my shapes when working in that Illustrator document.  Try to slice with the knife tool, nothing slices.  Try to select with the lasso tool, nothing selects.  I can copy the shapes onto a new document and the tools work normally.  So there's some kind of setting in that document that I would like to turn off.  Any gurus know how to do this?  Anything to save time. Thanks in advance!