In Decoration section of the Preferences window you can specify the default colors that are common across all the tools.

• Don't touch component – color of the components that must not be modified; gray by default.
• Problematic component – color of the components that create a problem; magenta by default.
• Problem fixer component – color of the components that are used for fixing the problem; orange by default.
• Problem-free component – color of the components that do not cause any problems; green by default.

• Highlighting color – color of the components under mouse pointer; amber by default.
• Selection color – color of the selected components; light blue by default.
• Shading color – color of the shaded component that are outside of the current group or page; grey by default.

• Excited component color – border color of the excited component in simulation; orange by default.
• Suggested component background – background color of the exited component that is suggested for the next simulation step; lime by default.