The common Estimation field inherits the default estimation field of the first selected Scrum Board and limits the custom estimation field dropdown option to the proper type:

• if it is a numeric field, then you can select only a numeric field

• the same is for issue count and time tracking type

• this function restricts accidentally adding hours and story points to avoid misinterpretation

• to change the type of fields available to select in the custom estimation field, you need to change the common estimation field value

The button, which opens the custom estimation field dropdown, changes its icon color to show that the estimation field is set for the particular Scum Board.

Click on cross in the dropdown unsetting the custom estimation field for the particular Scum Board.

The chart shows units used for calculation on the chart and in sprint details.