Zoom boxes (Show only / show all icons in course formats) confuse some students

in a topics-format course, the "Show only topic N" and "Show all topics" icons present a usability issue. Students who inadvertently click on them become confused when they lose sight of the the other blocks. It would be good if we could disable these icons, either at System or Course level, or perhaps through a new capability.

See discussion: http://moodle.org/mod/forum/discuss.php?d=92206