As of the time of this post, almost all of the Moodle 2.0 themes do not have a horizontal scrollbar for the grade content and this means that most of the grader report content is invisible.
For the grader report (which the teachers see) I did discover a CSS fix for the theme... and for the grader report one easy way around this is to make sure that "Static Students Column" is checked "Yes" unless your theme puts a scroll bar in the CSS. Barring this, you can add the following CSS to your theme (copy it first before making changes).
.path-grade-report-grader .gradeparent {
overflow: auto;
}
I don't think the above would apply to a student full report grade view but will investigate that for the formal_white theme at any rate. Maybe someone else that knows can chime in with more info.