Icons seem fine up to, and including 81 pixels.
At 82 pixels, they completely disappear. Clicking regions where icons were does nothing.
At 122 pixels, they reappear. However, they aren't functional, as in, clicking on them does nothing, ie highlighting or opening.
I've observed this on 3 different installs, and have had at least one other confirm this as well.
Fixed after RC2; you can find a patch attached to bug #1546.
*** This bug has been marked as a duplicate of bug 1546 ***