Userchrome Toggle

Userchrome Toggle is a powerful Firefox extension that lets you enable or disable your custom userchrome.css styles on-the-fly without restarting the browser. Normally, modifying Firefox's interface through userchrome.css requires a restart to apply changes, but this tool introduces a toolbar button and customizable hotkeys for instant toggling. It uses clever manipulation of the browser's title prefix with invisible UTF-8 characters to switch up to three different user styles seamlessly.

With options for notifications and a drop-down menu to select multiple styles, this extension caters to both casual users and hardcore keyboard enthusiasts. It respects your privacy by not connecting to the internet and has transparent code available for review. Userchrome Toggle simplifies deep Firefox UI customization with immediate feedback and high convenience.