What is the function of the lock icon in the dimension value edit dialog?

The lock icon in the dimension value edit dialog serves to prevent a dimension from changing. When the lock is activated, it indicates that the dimension is fixed, meaning that any adjustments to the associated geometry will not affect the locked dimension's value. This functionality is crucial in design and drafting environments, as it enables designers to maintain specific dimensions while making modifications to the surrounding components or features. By locking a dimension, the user can ensure that important measurements remain constant despite other alterations in the model, thereby enhancing stability throughout the design process.

In contrast, adding a dimension, hiding a dimension, or modifying aesthetics do not accurately describe the primary role of the lock icon, which is specifically focused on maintaining the integrity of dimension values against unintentional changes.