Sorry for the confusing title, but here's the issue - events where you can set number or slots for variables is not working when you click enter, you need to click on or out of the action instead.
Example: send random event - the events field is 3 by default, if I want to set it to 5 I can't by typing 5 and pressing enter. Instead, I need to type 5 and click away or on the action name with the mouse. Then I get the 5 slots for random events.
Happened when updated from Unity 5 to Unity 2018.