Selector Tabs Font Problem

Dear SAB-Team,
I have a problem considering the font in Selector Tabs (BOOK/CHAPTER/VERSE).
The displayed Font (in my case, font1) of BOOK/CHAPTER/VERSE in Selector Tabs is always changed back to the default or system font, as soon as man clicks the CHAPTER or VERSE Selector. Having tried to set the font for Selector Tabs to “font1” directly in the User Interface Styles, but it does not work. Could you give me a solution?
Thanks in advance!