This dialog box is accessed from the Options | Look & Feel... menu item or Tool Bar button.
The "Look & Feel" selection determines the appearance of ClassCracker.
Depending on the type of computer and the operating system, some options may have no effect (for example, the "Mac" option on a Windows system).
On Linux, the appearance depends on the fonts installed. If fonts appear too large with the "Metal" option, try the "Metal (small font)" or "Motif" options.