Disappearing added staff

I have made a score where I have added an extra staff above piano part and also below guitar part. I have now decided I want to delete the first bar, but when i do this the entire added staff for the piano and guitar part disappears. Is there a way to delete bars from the score without this happening?

If you view signposts, you should see “+1 staff” signposts where you added the staves.

Drag them into the second bar before you delete the first one.