Clicking between 2 epics with zero issues breaks epic filtering

When clicking between the 2 epics with zero issues no change is noted and so subsequently the epic cannot be deselected (unless an epic which does register a change is clicked).
miruflin noted the issue was introduced at https://bitbucket.org/greenhopper/greenhopper/changeset/7e11f95cf1f7e5d8f6c0a9766c90c77090c1194a

cc igrunert