getting screen location of a non canvas slate widget(Making a slide bar)

I am currently making something similar to a slide bar to set sound and brightness for my game.

Basically the setup is a SImage inside a wide SBorder.
And I want to drag the image between the border.

For this I want to know the location of the SBorder and the SImage inside it. Is it possible to do that without using canvas slots?

Cause arranging things will be harder if I use canvas slots.

—Edit—

Slate already has a SSlider and it saved lots of my work.

Although the problem is its just a single line and we can’t change its thickness…