Jaspersoft Studio 6.2.1 dark theme - xml is not readable

Hi, I'm using the dark theme in Jaspersoft Studio 6.2.1 (Under Preferences->General->Appearance), however, the only options I have for "Color and Font theme" are ["Default (current)", "Reduced palette", "Classic theme"]. As a result, the XML source of reports is unreadable (tags and attributes are dark blue on dark gray color), and there seems to be no way to change them. Under Preferences->General->Appearance->Colors and Fonts there is no category for XML at all.

Any ideas? How can I customize the colors in the XML source?

Thanks in advance for your help.