How do you add content to UMG in runtime like you do in the HUD canvas?
There appears to be no way to change or edit the layout of the widget at runtime or add new item to widget at runtime at desired locations.
Unlilke hud where you can just specify the co-ordinates of where to draw what there seems nothing like that available for UMG widgets. Is UMG made only for UI menus?
Try give me an example of what you mean.
Because quite frankly you could just make functions that does what you want them to, then call them outside the Slate Widget as getting the widget itself during runtime is fairly easy.
Lets say a radar screen with dots or other moving markers , this can be done in hud fairly easy but how do you draw or position something in UMG.
Now please you give me an example 
You have the function “OnPaint” which you can override and there you can draw stuff like in the hud.
Where is it? I can’t seem to find it
Quiet late answer, though the “OnPaint” node
can be found as "overrideable Function"
in a “User Widget” 
Blueprint
. So if you select it from the override selector in your widget you can do your drawing there. Adding components, like other widgets, can be done on a canvas panel
(or vertical box…). When you tick the box at "isVariable"
the component gets accessible in the blueprint graph, there you have a lot of options on what to do with the widget at runtime. Btw it is possible to place a widget in a 3d world too.