Checkboxes act unpredictably when sheet protection is enabled

[Gunther Maplethorpe]

When the attached workbook is unprotected, the checkboxes work fine. However, once sheet protection is enabled, the checkboxes start to act funny - clicking near the bottom of some of the boxes will check the box below it. It's as if the "area" for the checkbox is equal to the large drag-box around it that's visible when you go to move the object (don't know what that drag-box is called)...but, again, this only happens when sheet protection is active.

Has anyone experienced this before, or know of a fix?

There's an example in the attached workbook.