JIRA Agile Gadget Hours chart includes past Original Estimates as current if Original Estimate is removed

Create an item with 8h as the Original Estimate

Edit the item and remove the Original Estimate (remove it, don't enter 0).

Add an Agile Gadget to a dashboard, using a filter "key = <the item>".

Observe that the Agile Gadget's Hours chart indicates there are 8h remaining.

I expect 0h remaining instead.

JIRA (v4.1.2#531) GreenHopper