ABD6 - Stairs visibility on plan views

I can't figure how i can show the stairs on my Floor 1 plan view.

On floor 0, OK, stair is cut at 1 meter and we can this its start.(pic 1)

On floor 1, nothing. (pic 2)

But if i hoover the mouse on the drawing, 2D cell for stair is shown. (PIc 3).

How can you set the visibility of the stair located on floor 0 ( there is no slab on floor 1) ?