Deleting Individual Stair Stringers

[BigPicture045]

I need to remove the stringers shown below:

I can select the stringer; however, I cannot delete it. 

[RDAOU · Accepted solution]

@BigPicture045 

Delete is not possible... edit the stair type and remove it   

If you have other types where it is required.  Duplicate stair type and set up one with the stringer and one without