Please, whether there is a possibility for changing background color? White is very strong.
There are standards around (e.g for the European Community 90/270/EWG) that define the environment for work at the office at an electronic data processing device.
One of the described aspects is the best contrast to enable the use of computers also for people with degraded vision. The best contrast is black letters on paper-white background. In this respect does MP3tag comply with the standards.
So if you think the white is too bright then reduce the brightness and contrast of your monitor - this will help you much quicker than to wait for a modification in this program.