If you create a new notebook by importing from a powerpoint or pdf, then create a Protractor tool, the protractor is hidden behind the imported background image. To find/use the protractor you have to unlock the background image, add the protractor (or another object to the page), then send the background image to the Back in the ordering menu, and THEN you can see your protractor!

Proposed fix: New protractors (and other tools) should automatically appear in the top layer, and/or imported background images should automatically be in the lowest layer.

Thanks for taking care of this!
Alex