To repair photos with this defect, use Edit | Adjust | Chromatic Aberration… [Ctrl+Shift+A] in the Browser. In the Editor, use Adjust | Chromatic Aberration….
Chromatic aberration can have any of several causes; one cause is different refraction of rays of light with different wavelengths. Its effect in pictures is to give places with high contrast a purple, or occasionally green or blue, blurred contour. Zoner Photo Studio provides an easy-to-use tool for remedying this defect.
When there is no chromatic aberration in the center of a picture and it becomes gradually stronger towards the edges, you can fix it using the "Red-green" and "Blue-yellow" sliders. By using these to "push" the color channels towards each other, you will fix the defect.
But if the chromatic aberration manifests itself in another way or if the mentioned controls are not enough to suppress it, you can turn on the Desaturate a particular color controls. These let you selectively suppress colors in the picture, with a tolerance level of your choice.