1. You have drawn in a measurement to an image, e.g. a Distance measurement.

1. Select the measurement by clicking on it.
2. Click on the Properties icon in the measurement box.
   
3. The Properties dialog opens.
3. Select the desired unit from the Unit drop-down list, e.g. mm instead of µm.
   

1. The changed unit will be displayed in the image and in the measurement box.