How to enter a negative value in the Actual value of a performance goal measurement

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How to enter a negative value in the Actual value of a performance goal measurement

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Hi,

we would like to enter a negative value as Actual value for a performance goal measurement. When the performance goals have been created, for some of them (see the screenhot 'Negative_Target_value.png'), a negative Target value has been entered. However if I try to enter a negative value (the same behavior has been encountered for both Target and Actual value) in a new performance goal (or in an old one, without the Actual and/or the Target value) a data validation error appears which points out that the only allowed values must be >= 0.