This plugin adds a blue button to the compose screen, next to the identities selection dropdown. By clicking it, a textbox will replace the dropdown, allowing you to enter whatever you want as sender value (it must be a valid "From:" header field value, though).

When replying to an e-mail sent to you through an address not in your identities list, plugin will automatically fire and set "From:" header to the address the original e-mail was sent to.

Copy "custom_from" folder to your RoundCube "plugins" directory, then add a reference to this plugin in your "config/main.inc.php" file. Ensure that your web user has read access to the plugin directory and all files in it. Custom sender button will appear at the right of the identity selection list.

If you want to disable the "automatic replacement on reply" feature, rename "config.inc.php.dist" file into "config.inc.php", uncomment the line with a parameter named "custom_from_compose_auto" and set this value to "false".

• dwurf (https://github.com/dwurf) for the globals $IMAP and $USER fix