How to use UMG navigation with world space widget?

Hi,
First, I know how to use UMG navigation with “normal” widget. I usualy do this and it works fine:

Now, I need my UI to be rendered in world space because i’m working on a VR game, so I’ve set up my pawn like this:

116499-widgetsetup.jpg

The UI is showing fine but when I tried to use navigation on this widget, I tried this in the widget blueprint: (the delay node was use as a workaround but removing it doesn’t change anything

But it doesn’t work. I don’t have focus on this button, using keyboard arrows or gamepad doesn’t highlight other buttons, etc.
As you can see, I’ve already tried to check the “window focusable” in the widget component details but it’s doesn’t change anything

I still need help with this please…

Anybody found something about this?