theme_boost: Grade View in Course doesn't show student names when sideways scrolling

In Boost and Clean, in English and Hebrew, and all supported browsers - view the grader report when there is a long list of grade columns for the course. Verify that: Instead of having in-content scroll bars - the entire page scrolls to the left or right. When scrolling the user column is always visible. The user column should stick to the edge when required * See note Any blocks for the page are shoved to the bottom so that they dont sit "under" the grading table. Note - I notice on linux / chrome at least in RTL the header sticks "under" the vertical scrollbar. However - I assume for a RTL OS the scrollbar would be on the other side.