Different fonts may be specified for different purposes. In some programs this is merely a cosmetic feature, but in this case, in some circumstances, it can be quite important. For example, if you are working with data in one writing system and the interface in another, there is good chance that, even if you have a single font that covers both, you will prefer to use different fonts since different fonts are stronger in different writing systems.
You can choose the font family, size, and attributes by selecting Select Font from the Configure menu. This pops up a control panel like the one illustrated below.