Can't adjust height of half wall

[LennyOgg]

For some reasons I cannot adjust the height of this one half wall.
When I try the ones at the side or below, it’s possible ö.Ö
Maybe because of the stairs?

[LennyOgg]

When I remove the stairs it works again.
It should be possible to adjust the height with stairs attached.
And when I change wall type or to handrail, the stairs get deleted, this shouldn’t happen either