I wanted to post my observation here first instead of in the ideas area. In order to easily enter grades manually for an assignment, I reduce the width of my browser window so that only one column of grades is visible. If I want to add comments for a student and see all of the comment as I write it, I have to resize the comment box to fit in the visible space. Resizing works great, but the submit button stays in the lower right corner of the original box (and off the visible browser pane). Therefore to submit I have to scroll to the right to get to the submit button. it would be nice if the submit button would move with the comment box.
I don't really consider this an idea rather a bug or quirk with Canvas. I could write it up as a feature request, but it does not seem to be of that level.