I am pleased to see that macOS 10.13 now allows pasting into the password field of authorisation windows, e.g. the prompt that appears when unlocking System Preferences:
With macOS 10.12, copying/pasting was prohibited, so it was necessary to reveal the password in 1Password and manually type it in.
I appreciate that this is predominantly a support forum, but I wanted to share this with anyone considering upgrading to macOS 10.13.
1Password Version: Not Provided
Extension Version: Not Provided
OS Version: macOS 10.13
Sync Type: Not Provided