FSlateDrawElement::MakeText drawing to same layer

I am making a custom widget and part of it is using the API FSlateDrawElement::MakeText, however when I pass in different layer values all the text appears to be rendered on the same layer? Is this a bug or am I missing something?

FSlateDrawElement::MakeText(
OutDrawElements,
++CurrentLayer,
PaintGeometry,
AgentText,
FontInfo,
ESlateDrawEffect::None,
FLinearColor::White);