Feature summary (what you would like to be able to do and where):
Hi,
As a sysop, I'd like to have a capability to restore partial block settings when I need to apply a temporary full block over it.

Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):
Imagine a user who has a long-term/indefinite partial block applied. Also, the user cannot mention a certain subject anywhere, including his/her talk page. If the user violates the topic ban (for example, mentions the prohibited subject on his/her talk page), I want to apply a temporary full block to him/her. But I have to remember when the full block starts and when it will end. After the full block ends, I have to restore the previously applied partial block (otherwise, the user will be free as Dobby :), which is not my intention).
When editing block parameters, it would be great to have an option that remembers previous block settings and allows me to automatically restore them after the edited block ends.

Another situation when this feature could be applied is an editor with a partial block who is edit-warring in an allowed article. Again: a temporary full block overrides a long-term/idefinite partial one and a sysop has to restore previous block settings.

Benefits (why should this be implemented?):
More flexible prevention of rule violations.