Persona switcher adds a submenu to "Tools" that allows you to quickly switch between themes. It adds the following three user-definable key combinations.
- Shift-Alt-D to reset the theme to the default.
- Shift-Alt-R to rotate through your themes.
- Shift-Alt-A to start or stop switching between themes on an on-going basis.
You can customize the key combinations via "Manage Extension Shortcuts" in the about:addons page. There are several other ways to customize theme switching using the preferences.