refreshVScaleMenu() was unconditionally removing the cal-invalid class from all three calibration inputs, which silently cleared the red-border error indicator on a field the user was editing whenever a hub calibration broadcast arrived. Apply the same focused-element guard already used for .value writes so a rejected value's error styling persists until the user corrects it. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>