So… Hopefully… my last problem with UI in common… not just common UI… By default, unreal handles the directional Inputs by default Input Methods. Keyboard-Cursors, Gamepad D-Pad AND… Analog (Thumb-) Sticks… Last one is a Problem… since i want my Player being able to walk around, while f.e. the I…

Which would make the Inventory not controlable while walking. I made a compromise by switching Left and Right Thumbstick via custom Slate Navigation. Not perfect, but acceptable .