My dear reader may think this is a joke, but it’s not: I am using for more than two decades office software, but I never needed to spent several minutes of checking 0. the program 1. the help and 2. the internet to find a solution for such a simple task. LO < 4 had some simple “Insert – horizontal ruler”-menu-entry. But why keep something well established?
Solution: enter three dashes and press and pray for the auto-format!
The next entry should have been about improved, stabilized and un-dithered GIF. Will follow (soon)!