Hi Chris Thanks for getting back to me. You are correct - that does open speed grader in a new window, however from my experience it also opens the document to be marked in the same window. This means that the rubric is only partially exposed. In Moodle for example, the window with the rubric can pop out so that you can see the whole rubric width - much easier to mark in this way.
See this image of how it looks with Canvas:
speedwriter 1.PNG
See this image of how it could look with a popout window:
Speedwriter 2.PNG
I'm aware that the border can be controlled to view the whole rubric, however that reduces the size of the document being marked. I thought that a detachable window might be a useful addition.
shaby