Preview stuck on markup tool

I used Preview v 9.0 Mac OS 10.12.6 to markup an image.

Now when I open any image e.g. a screen shot in Preview, it is stuck on the last markup tool I used (the Add Rectangle Tool).

What I need to do is to tell Preview not to use ANY Markup Tool on an image but I cannot seem to do it.

Any idea how to accomplish this?

thanks

Caroline