1. Choose File menu > Manage > Themes.
You see a list of all the themes available in the file. Predefined themes (themes that come with FileMaker Pro Advanced) are enclosed in brackets ([ ]). The # of Layouts column shows the number of layouts that use each theme.
2. In the Manage Themes dialog box:
To  | Do this  | 
Rename a theme  | Select a custom theme, click Rename, then type a new name. Tip By default, a custom theme has the same name as the predefined FileMaker Pro Advanced theme on which it is based. To avoid confusion, rename the custom theme.  | 
Duplicate a theme  | Select a theme, and click Duplicate.  | 
Copy and paste a theme  | When the Use advanced tools general preference is selected, select a theme and press Ctrl+C (Windows) or Command-C (macOS), then press Ctrl+V (Windows) or Command-V (macOS). Note See Setting general preferences.  | 
Delete a theme  | Select a theme, then click Delete.  |