Don’t work in 4.15 or 4.16 etc
The Arrow component back to default size without reason
Make a new Blueprint.
In the Blueprint add an arrow component, where you add the visual components.
Set the arrow some color in the panel of settings.
Now make a new var of type Integer in the Blueprint, and set the var editable with the eye.
In the construct of the Blueprint add the Get of the new integer var, connect to a / node (Integer / 10) and connect the result to the arrow → set size connect this node to the construct.
Now save all place this actor in the world.
At slide the int var the size of the arrow changes is fine.
Now move it over the world and the arrow back to default size without reason.
Edit another time the var and back to other size, move another time and back to defautl size wtf.
And that is all.