How to lock in parameter value?

Some parameters have a small button with a lock on it on the left of the parameter's name. These Lock buttons allow to fix the parameter value to avoid an accidental change or a change due to interrelation between parameters.

Example of using Lock buttons (measuring parameters of mounted diamonds).

The user measures diameter and total height of the diamond and enters them in Diamond Calculator, then fixes total depth with Lock button. After that, measuring the crown height and entering it into the software will cause an automatic adjustment of current pavilion depth and girdle thickness in such a way that the total height will not change.

Parameter fixing is also very useful in diamond marking for maximizing the diamond mass with respect to restrictions imposed by a diamond with old cut, a semi-cut diamond, or a rough diamond.

Note: If a proportion allows a choice of units of millimeters or percents of diameter, only the value in percents will be fixed when Lock button is checked, even if a value in millimeters is displayed currently.