Confidence spinner
From FLWiki
A confidence spinner is a spinner that appears on each entity when the View > Confidence command is selected.
If the confidence value of the entity is within the range 0.0 … 1.0 (the normal range for a fuzzy boolean) then the confidence spinner displays the value as a percentage pie-chart. If the confidence value is out of that range, it will display as a filled red circle, but the correct floating-point value is maintained internally.
