What happened to my shift key?

I can't seem to get my shift key to work.

I just want to make controlled likes kinda like connect the dots? I am tracing an edge. I used to be able to hold my shift key and it would make a straight line from click to click, but now all of a sudden it doesn't do that. Do I have some control or toggle switch on somewhere that I don't know about?

Thanks

(I'm kinda new)

Well I found a search string, just after I posted this, ARRGH sorry, I really did search before I posted. However, it suggests to reset the tool, how do you do that?

I got it! However this may be good for someone else who needs it!