bucket tool with select “close large gaps” does not work

[Jennifer302193387r4p]

I want to fill color in non close line work of circle. In order to do that, I select "close large gaps" in bucket tool.

But it won't work. 

[Vladin M. Mitov]

How large are the gaps you’re trying to fill?
In my opinion, even with the "Large Gaps" setting, the bucket tool might not be able to close a contour break larger than 10-15px.