The title asks the question, but I know it's a bit confusing without a visual, so here's some screenshots!
Important Note: All screenshots are of a test account in a test assignment of a test course and were as titled only after selecting the "View Rubric" button to enable the selectable rubric for grading.
|SpeedGrader Initial Load without Global Includes|
|SpeedGrader After Using the White Draggable without Global Includes|
|SpeedGrader After Using the Grey Draggable without Global Includes|
The grey draggable, which is easily noticable, resizes the document viewer (#left_side) and the grader (#right_side) as is expected for a draggable that splits a page.
The white draggable, which is harder to spot and immediately to the right of the grey draggable, resizes the rubric (#rubric_full) without any consideration of the width of the grader window, which results in a horizontal scrollbar whenever it is accidentally clicked and dragged when actually trying to use the grey one.
So, what is the intended purpose of this second draggable? All we can determine is that it causes confusion when faculty try to resize the pages to better balance the document viewer with the grader.