Fonts not changing with drop down choices

I recently purchased the Aegaeus theme and am having trouble with the fonts. When I try to change the fonts using the selections provided in the drop down menus in fonts section for the theme, the changes do not apply and/or they do not match the chosen selection. Can you tell me how to correct this? When you change the fonts using only the drop down menus, should the button to enable custom fonts be checked or not?