Add to viewport goes fill screen, but the widget size should be custom

Hello, i just want to add a widget to viewport when i click on a button in another widget but the widget i will create goes fullscreen but i just want it to be as big as the custom size i set it in the umg editor

and i dont want to bring it in the other widget, because i need to create it when i click on the button and not just set it visible.

i just didn’t set it up with a canvas panel

but then you cannot anchor it and have a fixed position, how do you deal with this ?